Callie and Jeff Cargill pull up to the high school soccer field. They both sit in the car anxiously looking ahead. Callie points out that it's Jeff's last soccer camp before he's officially a freshman at the school. Jeff's a bit nervous. Callie and Jeff step out the car and walk towards the field together — Jeff to start practice and Callie to give Coach Ryan a check for Jeff's camp registration. They approach the other players warming up, but there is no sign of the coach, which is odd because he's usually on time.
Callie is about to head off, but stops when she hears distant shouting coming from across the field. She looks over by the bleachers and spots a female student waving and screaming for someone to call 911. Callie tells Jeff to stay put as she runs over to find the coach lying on the ground with blood on his shirt, shot. She gives him mouth to mouth, but it's too late. Jeff and the rest of his teammates watch in horror.
The high school field is now a crime scene, with dozen of cops and techs working the area. Detective Jim Longworth gets out of his car and walks towards Callie, who's finishing up her statement to police. She tells Jim that she has known Coach Ryan since Jeff was 8 years old and he was one of the most popular teachers at the high school. She says Jeff, who looked at him as a mentor, is really shaken up over what happened. Coach Ryan took him under his wing when Jeff's father, Ray, went to prison. Jeff was looking forward to seeing his familiar face once he started school. Jim looks over to the bleachers and sees Jeff, crying.
Carlos Sanchez joins Jim and Callie, telling them that the coach was shot through the heart at close range with a .38 caliber gun. There was a large exit wound. Callie tells them both that, according to some of the parents, students were talking about a freshman who brought a gun to school named Shane Wyatt.
Carlos, Jim, and two uniformed police officers walk into Shane Wyatt's sunroom, where he and his older cousin, Blake, are playing ping pong. Shane mother, concerned, watches as Jim questions Shane about the shooting. Shane admits that he brought a gun to school, but it was a pellet gun. After Jim asks him if he can see the gun, Shane stays quiet. So Jim has Carlos administer a gun shot residue test (GSR test) on his hand to see whether he fired a real gun recently. Shane's hand shakes violently as he's given the test and his family nervously watches.
Jim, Colleen Manus, and Carlos walk through the station to the interrogation room. Carlos reports that the GSR test came back positive, and now it's only a matter of finding out where Shane stashed the gun. Manus is getting a search warrant for Shane's locker. She hopes they'll also be able to find information in the locker indicating why he targeted Coach Ryan.
The three stop outside the interrogation room where Shane sits, alone. Jim looks inside, clearly not ready to interrogate a 15-year-old. He says, "Sometimes I really hate my job."
Jim walks inside where Shane is sitting at the table in the middle of the room, clearly frightened. Jim tells him he doesn't want to make this harder than he has to be, but he needs to open up to him. Shane continues to claim it was a pellet gun, but Jim says he needs the gun to prove or disprove that it was a pellet gun. Shane finally lets up, and tells Jim that he dumped the gun, which was a .38 caliber and not a pellet gun, in the canal. Jim notices the bruises up and down Shane's arm, and tells him he understands that high school bullies can be tough to deal with. Shane tells Jim that it isn't just one bully, but that basically everybody picks on him all of the time. He brought the gun to school to scare the bullies so they would stop teasing him. He admits that Coach Ryan found out he had a gun and said that he understood what he was going through, but didn't want him to do anything that he would regret for the rest of his life. In a struggle to take the gun away from Shane, it went off and he was killed. Shane swears he didn't mean for that to happen and that he really liked Coach Ryan. Jim asks Shane where he got the gun and Shane tells him he purchased it from a sporting goods store. Jim questions his ability to get a gun from a sporting goods store, and Shane finally admits that he bought it at a flea market.
Jim walks into the flea market, spotting Clay Malone's gun booth. He walks towards Clay, pretending to be interested in purchasing a firearm. Jim tells Clay that he's looking for something bigger than a Beretta and Clay takes him under the tent to his "bigger stash" where he has an array of AK-47s and other large guns hidden under a tarp. Jim picks one up and Clay tells him that it would be a cash transaction and that he has to know whether he has a police record before he can sell the firearm. Jim finally admits he's a cop by bragging about his arrest record (most closures in a single year and an 85 percent arrest-conviction rate). He asks Clay about his own record, which Clay says include two convictions for petty theft. Clay maintains he's allowed to sell guns from his private collection but Jim counters that he's not allowed to sell them to minors and holds up a picture of Shane on his phone. Clay swears that he didn't sell any gun to any minors, saying "Do I look like that big a dummy to you?" but Jim has a hard time believing him.
Manus and Carlos stand over Daniel Green at his desk. Manus says they searched Shane's locker and, while they didn't find the gun, they found a box of ammunition and a receipt from Gerry's Sporting Goods store. Daniel brings up the security footage from the store where they see Blake, Shane's cousin, purchasing the ammunition. Manus tells Carlos to call Jim and to meet him at Blake's house.
Carlos and Jim arrive at Blake's house. The shades are drawn and inside the apartment a loud movie is playing. Carlos and Jim knock. No answer. Carlos continues to pound away at the door. Then Jim notices a bullet hole in the apartment window. Jim draws his gun, pushes Carlos away, and slowly opens the front door. Carlos and Jim enter the apartment where they see the TV, which is on full volume, with Blake shot dead next to it.
Callie cooks dinner while Jeff does his homework at the table. She looks over at him and sees that he's clearly having trouble concentrating. She tells him that they should both take the day off tomorrow and drive up the coast and rent some wave runners. Jeff, somewhat annoyed at her attempt to make him feel better, tells her that he can't because he has a big test tomorrow at school. She says she's worried about him, but he says he's fine. He answers an incoming phone call from a friend (sounding happy and cheerful), and leaves Callie alone at the table.
Now a crime scene, Carlos and Jim walk out of Blake's house. Since there was no sign of forced entry, Blake must have known the killer and he must have been shot inside. They meet up with Daniel, who's putting wads of $50 bills in a plastic bag as evidence. He tells the guys that he found the money, which added up to about $60,000, in the back of Blake's closet. Carlos and Jim look at each other, knowing that a part-time ticket movie ticket collector doesn't make that kind of money and that he must have been doing something shady on the side. Realizing that the gun probably did come from Clay, Jim tells Daniel to check and see if his fingerprints were on the money. He'll be able to tell since Clay's prints are already in the system.
Manus, on the phone with Jim, tells him that she ran a background check on Blake and that he was the registered owner of over 100 guns. Jim tells her that they didn't find any guns in Blake's house, only the cash. Manus says she spoke with her contact at ATF who told her that Blake was on their radar as an up-and-comer in the black market. He's suspected of selling new and stolen guns to felons and gang members. Manus tells Jim that he bought all of the guns from the same place he bought the ammunition, Gerry's Sporting Goods store.
Jim arrives at the sporting goods store and confronts the Gerry, who's working the counter. He asks him if he knows Blake. Gerry says he does, and that Blake is a customer. Jim tells Gerry that Blake was just found dead and asks him why he sold him 100 guns. Gerry tells him that he wasn't about to turn down an order like that. Jim tells him that he believes one of the guns Gerry sold to Blake wounded up in the hands of a 15-year-old who may have accidently killed his teacher. Jim then tells Gerry about the illegal black market iron trade Blake was involved in and asks Gerry if he had any involvement in that. Gerry says that if Blake was reselling the guns he sold him to felons, then he deserved what came to him. But Jim says that maybe Gerry killed him because he didn't want Blake to rat him out in his involvement in the operation. Gerry chuckles and tells Jim he runs a legitimate business. It was totally legal for him to sell Blake, who was 21 years old, the 100 guns. Jim, not buying any of it, calls Daniel and tells him to run financials on Gerry Whitlock and his store. Gerry looks concerned and Jim tells him that if he found out that Gerry sold the gun that killed Coach Ryan, then he would make it his mission to put him behind bars.
Back at the station, Manus tells Jim that Shane was arraigned in juvenile court, but is still sticking to his story about buying the gun from the flea market. Carlos approaches Jim and hands him Blake's autopsy report, telling him that Blake's time of death was between 4 and 5 p.m. Jim asks Daniel to check all of the traffic cameras around Blake's apartment at that time. Daniel reports that, as suspected, the lab found Clay Malone's prints all over the money. Daniel brings up the fact that Blake was buying new guns from the sporting goods store, but that Clay was only selling used guns. Jim then explains his theory that Blake would file off the serial numbers and then sell the guns to Clay as "stolen" because felons will pay up to ten times their retail value for a gun they can't legally buy and that can't be traced back to them. Jim grabs the bags of money from Daniel and heads to the evidence room.
Jim enters the evidence room holding the bags of money and greets Ed Vickers, a by-the-book evidence custodian checking in evidence. Jim tells Ed that he needs to submit the cash as evidence and then check a few stolen weapons out. Ed tells Jim that he doesn't have the authority to do that and none of the items in evidence leave his possession. Hearing this, Jim has an idea.
Back at the flea market, Ed nervously carries a duffle bag and walks slowly toward Clay's gun stand as Jim watches from his car. Ed, who's wearing a wire, tells Jim that he's unsure about doing this, but Jim encourages and assures him that he'll be fine.
Ed approaches Clay at his booth and tells him that he's heard this is a place where he could "lighten his load." Ed places his duffle bag on the counter and Clay, at first reluctant, agrees to see what he has. They go into Clay's tent, where Ed assures him that the guns are untraceable. Clay names his price, $300 per gun, and Ed fumbles with his wallet and then accidentally drops his FDLE identification. Ed, realizing that he's now caught, reaches for a gun inside of his duffle bag and points it at Clay who rips it out of his hand and draws the gun back on him. Just in time, Jim rushes into the tent and grabs the gun out of Clay's hands and cuffs him. Two undercover officers, who had been waiting outside, come and take Clay away.
A slightly ticked off Manus approaches Jim back at the station, asking why he used Ed undercover. They both look at him through a window, he's outside drinking a cup of coffee and shaking while smoking a cigarette. He doesn't normally smoke. Manus tells Jim that Daniel ran Clay's finances and he's been involved in a number of off-the-book businesses. Jim says he thinks Clay may have killed Blake because he looked like he could have killed Ed during the sting operation. Jim asks Manus about whether the FDLE divers have found the gun that Shane supposedly threw in the canal, but she says no.
Jim enters the interrogation room and sits across from Clay questioning why he would draw a gun on an FDLE officer. Clay claims he was only protecting himself and his stand, which he has a right to do. Clay maintains he's never sold a gun to a felon and that Jim won't be able to prove that he did. Jim tells him that they're getting to the bottom of his cash-only businesses and once they find the gun that Shane used to kill his teacher and prove that he's selling stolen weapons as if they were part of his private collection, he'll get 10 years in jail for that and another 20 for murder. Jim tells Clay that they found $60,000 in Blake's closet with Clay's fingerprints all over it. Jim says that he knows Blake was Clay's straw man and that Clay murdered Blake to avoid his involvement in the black market gun trade coming to light. Clay slides across the table closer to Jim and tells him that he didn't kill Blake and he's rather blow his head off then see the inside of a jail cell and that if he did, why didn't he take the money found in his apartment? Jim says, "Because as we've already established, you're not that big a dummy."
Outside in the main office, Callie sits and fills out paperwork as Carlos walks by and asks her how Jeff is holding up. She tells him that he's still taking the Coach Ryan's death pretty hard, and not talking about it. Plus things aren't getting any easier with him starting high school next year, since he won't know anybody there. Carlos tells her that he had the same problem when his daughter Addy went to high school, but that she found it easier once she became friends with older students who were able to teach her the ins and outs of things. Callie tells Carlos that she doesn't think Jeff knows any older kids, but Carlos asks if she's sure about that.
Jim knocks on the Wyatt's door, and Shane's emotionally drained mother lets Jim in. She tells him Shane isn't doing well — he's not eating or sleeping — and the kids at school are tweeting that he is a murder. She also tells Jim how much Shane loved Blake and that he was there for him during her divorce. Jim asks to talk to Shane to find out where he got the gun so they can prosecute the seller. He says that while the Coach's death is not his fault, he will have to live with what happened for the rest of his life. Shane's mother agrees and heads upstairs to get him. While she's looking for him, Jim notices Shane and Gerry Whitlock in a framed soccer photo along with Coach Ryan and the rest of the team. Some of the team members are holding up a banner for their sponsor: Gerry's Sporting Goods Store. Shane's mother hurries back to the top of the stairs and tells Jim that Shane is gone.
At the high school soccer field, Shane hangs over the top of the bleachers, looking down on the spot where Coach Ryan died. Pale and bowed by the weight of the terrible accident, he wipes away some tears. Fastened to the top of the bleachers is a rope. He lifts the other end of the rope and loops it around his neck. Before he can jump, Jim arrives and stands at the bottom of the bleachers, telling Shane that killing himself won't bring Coach Ryan back. Shane tells Jim to stay back and that he has to do it. Shane tells Jim about the Coach's new baby, who will now grow up without a father. Jim says that what happened was a terrible accident and that Shane can get through this and that his mother needs him. He continues that Coach Ryan wouldn't want him to kill himself. He reminds him that the Coach was trying to get Shane to realize that his life was worth living. Shane starts to shake and cry. Jim runs up the bleachers and stands with Shane who crumbles into his arms.
Jim barrels into Gerry's store, still riding the emotion from talking Shane out of taking his life. Gerry's helping a rough looking, tattooed customer, who is checking out an AK-47. Grabbing Gerry by his vest, Jim pulls him over the counter and asks him why he shouldn't believe that Gerry killed Blake to keep his side gun selling-business a secret. Jim also tells Gerry that he found out the store is bringing in way more money than Gerry's claiming. Gerry swears that he doesn't have a gun-running side business but admits that he lied on his taxes to prevent a megastore from setting up shop next to him and putting him out of business.
He adds that he's upset about Coach Ryan's death. They were friends and he coached both of his girls. Jim suggests Gerry killed Blake after feeling upset or guilty about how one of his guns killed the Coach. Gerry, upset at Jim's accusation, screams that he didn't kill Blake. He then tells Jim that he has heard that the cops haven't found the gun used to kill the Coach yet so he knows nothing has been traced back his store. Jim admits that they haven't found the gun yet but assures Gerry that when they do, he'll be back.
Callie, in the kitchen, prepares a large salad when Jeff walks in, asking her why she's making so much food. Callie tells Jeff that they are having guests over for dinner, but before a confused Jeff can ask who, the doorbell rings. Jeff answers the door to find Carlos and his daughter Addy standing there. Callie invites them all in while Jeff closes the door looking slightly annoyed.
At the station, Manus tells Jim and Daniel that Clay has made bail. Daniel brings up the traffic cameras on his computer and says Gerry is the registered owner of two cars and Clay owns one. None of those cars appeared in Blake's neighborhood during the time of his death. But he does point out a suspicious-looking van that was no longer registered and shouldn't be on the road. Jim tells the group that in addition to guns, Clay sells auto parts at his flea market stand. So perhaps he built the van using parts from the junkyard and/or owns a junkyard that isn't listed under his name. But car parts are computerized, so if any of the parts used to make the car were listed for sale, Daniel can get an address. Manus tells Daniel to check junkyards around the area to find out which one sells part belonging to that van. If they can trace one of the parts of the van to Clay, that puts him by Blake's house at the time of his murder.
Callie, Carlos, Jeff, and Addy awkwardly sit around the dinner table while Carlos and Callie try to initiate conversation between the two youngsters. Realizing Addy and Jeff are not happy with their ploy, Callie and Carlos get up to get dessert. While they're up, Jeff apologizes to Addy for the "lame and embarrassing" situation. Addy notices Jeff's gaming system in the living room and they immediately connect, heading into the other room to play some video games. Callie and Carlos return from the kitchen to see their kids laughing and bonding on the couch.
Jim arrives at the junkyard where he spots the same black and white van from the traffic footage near Blake's house. He's on his cell phone talking to Daniel, but the phone service is no good and they lose each other. He hops over the fence and walks towards a shed near the van. After breaking the lock, Jim walks in to discover that it's full of hundreds of automated weapons and handguns. Jim steps outside and pulls out his cell to make a call back to the station to let them know about his find, but still doesn't have service. Suddenly, bullets rip by him and he looks up to see Clay behind a stack of cars, firing at him with an assault riffle.
Jim immediately takes cover and begins to shoot back. Jim dives beside the shed and fires at Clay, who takes cover. Jim has no choice but to move. He fires at Clay as he runs toward a row of stacked cars. Clay ducks, but then fires back. Breathless, Jim spots a school bus across the way and by counting the shots, he is able to dash towards the bus while Clay is reloading his weapon. Clay follows him onto the bus and starts ripping shots. Jim triggers the remote STOP sign on the side of the school bus and it pops out, startling Clay, who turns and shoots at it. Jim, his gun pointed directly at Clay, tells him to drop his weapon. Clay pulls the trigger, but his magazine is empty. Clay drops the gun and before he can reach for another at his hip, Jim shoots him in the shoulder. On the ground and bleeding, Clay tells Jim that he doesn't want to go to jail and that Jim should have just killed him when he had the chance. Jim says he doesn't want to have to live with that.
The scene is now crawling with police and medics, and Clay tells Jim that he'll admit to the gun charges, but he still swears he didn't kill Blake. He did buy stolen guns from him the night he was murdered, but Blake was alive when he left. The medics take Clay away as Manus approaches Jim, in awe of all of the guns that were confiscated. Manus goes through the guns and shockingly questions how Clay or Blake even got a hold of any of these since they were so difficult to find on the street. She tells Jim that some of the guns, the HK416s, were similar to ones she confiscated on drug busts years prior. She says she doesn't even know where you could legally get one of them. Then she spots a Browning Citori, another type of gun, and says ATF confiscated similar guns from an outlaw motorcycle gang which gave them out to its members when they joined. She says that Clay must have a great source for getting those kinds of guns at such a high volume. The uniqueness of the guns, and the "source" behind them, gives Jim an idea.
Jim enters the Wyatt's sunroom where Shane sits with headphones on. Jim tells Shane that he knows Shane didn't drop the gun into the canal and that if he hands over the gun, Blake's killer can be caught. Shane gives Jim a look that says he'll cooperate.
Jim, Carlos, and a uniformed officer approach Ed in the evidence room. Jim holds up the gun that killed Coach Ryan and tells Ed that even though he tried to scratch out the serial number on the side of the gun, hydrochloric acid can make the numbers reappear. Carlos says ballistics will prove that the gun in the bag was the one used to kill Coach Ryan and that it was also used in a previous crime and then ended up in Ed's evidence room. Jim tells Ed that all of the weapons they found at Clay's shed have been in that evidence room before and they were never "destroyed" as Ed said they would be. Carlos says that they know Ed sold the gun to Blake and that after Coach Ryan was accidently shot by Shane, everything would be traced back to him, which is why he killed Blake. Jim cuffs Ed who tells them that after working for 14 years in the evidence room, he has realized that no matter how hard they try to get guns off the street, it doesn't matter, because they will just wind up back in the same hands.
Jim walks through the substation with the deputies who escort Ed out in handcuffs. Jim spots Callie watching this, alongside Shane Wyatt and his mother and he peels away to join them. Jim tells Shane that since the shooting of Coach Ryan was an accident, he has no prior juvenile record, and he helped Jim catch Blake's killer, he can go home with his mother. Shane and his mother leave and Jim is left standing with Callie. He asks how Jeff is doing and Callie tells him that he's doing a lot better and that he and Addy have really bonded over the dramas of high school. Jim looks at her and says that sometimes knowing that there's somebody there for you can make all the difference in the world. Their eyes meet and they hold each other's gazes for a moment.
Jim asks Callie if she wants to go for a beer. She says, "That sounds great." Slowly, that look between them becomes a welcoming smile. He and Callie walk away together.
At a beachfront restaurant, Jeff is gathered around a table with Addy and a bunch of friends, socializing and drinking a soda. He looks comfortable.
Shane leaves a convenience store filled with teenagers. They all look at him and whisper. He leaves the store looking sad and walks down the street alone.