Moments after shooting Warrick (Gary Dourdan), undersheriff McKeen (Conor O'Farrell) calls in an "officer down" to dispatch. He fails to mention he's the one who downed the officer. He calmly walks down the alley, describing his "chase" of a non-existent suspect and car. He evenly says he's in pursuit.
At a nearby newsstand, Grissom (William Petersen) hears the call over the radio. He rounds the corner and realizes it's Warrick. When he reaches him, and despite disturbing the evidence, he pulls Warrick's limp body from the car and cradles his head as he spits up blood. McKeen runs back, telling Grissom he was first on the scene. He sees Warrick is still breathing. He puts his hand on his gun, in case Warrick is able to talk to Grissom. Warrick says nothing. And then stops breathing. As his killer checks on the paramedics, Grissom cradles the head of his dead friend.
A slow-motion scene shows Catherine (Marg Helgenberger) arriving. Nick (George Eads), Brass (Paul Guilfoyle) and others are already there. She sees Grissom squatting by Warrick as they pull a sheet over him. Grissom is covered in blood.
McKeen tells his story to Brass, saying he was walking west towards the diner to tell Warrick he was cleared. He says he heard the shots and turned into the alley and saw the suspect. He thought Warrick was dead so he ran after the suspect and called it in. He describes a late model dark 4-door sedan with a partial plate GRV conveniently, Pritchard (David Gianopoulos)'s car. Brass takes the bait. "Who else could it be?" says McKeen.
Dawn breaks in the alley and they're all still there. Ecklie (Marc Vann) arrives and asks Gil how he wants to handle it. Gil wants the case. Nick says he feels sorry for whoever did this.
They need Gil's clothes to process. He rides with Warrick, wheeling him into the morgue. Dr. Robbins (Robert David Hall) is going to sit this one out. Greg (Eric Szmanda) returns and asks for a task. Wendy (Liz Vassey) stares off into space. Hodges (Wallace Langham) bags Warrick's clothes, then Gil's.
Nick and Catherine work the scene. He finds a bullet, a .25. She finds the pistol. Nick thinks it was a hit. They think it was Pritchard. One of the shots came from inside the car. The window was down. Catherine accurately describes how she think it happened. GSR on the inside of the frame proves she's right. But why was his window down?
Brass pulls everyone off all cases except Warrick's, IDing Pritchard as the suspect. Gil returns to his office. Sara (Jorja Fox) is there. She caught the first flight out. She hugs him. Gil quietly describes Warrick's last moments. He didn't want to go. Sara tells him there's no where else in the world Warrick would have rather been at the end. He loved Gil and Gil felt the same. Catherine arrives. More hugging. Then Greg and Nick. Sara offers to help with the arrangements.
Nick knows Warrick wanted to be buried next to his grandmother. Catherine has a key to his place from when she got him clothes when he was in custody. Nick resolves they'll finish this for him.
McKeen stops by to talk to Brass, saying there's something he needs to get off his chest. He doesn't want Brass to think he had it in for Warrick. He's feeling "guilty" because he thought Warrick killed Gedda. Brass admits he thought the same thing. Brass feels badly, because the last thing he told Warrick was "I hope you remember how lucky you are."
The team gets to work, testing the gun and the bullets, swabbing. Catherine uncovers serial numbers. Nick checks the car covered in his friend's blood. The keys are in the ignition but the radio is turned down. He rolls up the passenger side window. Prints.
Greg and Sara go to Warrick's place. He never finished unpacking. Greg finds a picture of a young boy and one of the team. Then he finds paternity results. Warrick has a son. The papers indicate he was fighting for custody.
Catherine traced the gun to an armed robbery on which Pritchard was the arresting officer. The log says it was destroyed. But he would have need someone to fudge the records. Gil wants to know why he'd kill Warrick with a gun that could be traced to him.
Nick reports on the prints. Not fingerprints -- knuckle prints. The volume turned down and the knuckle prints make him think the killer knocked. (He's right.) Warrick never would have rolled down his window for Pritchard after Pritchard just tried to frame him. He wouldn't. Nick suggests McKeen.
Sara brings Warrick's psych evaluation tape to Gil. In it, he talks about how he never had a dad but there was a man in his life that always set him straight. He talks about everything he learned from him.
Gil, Nick and Catherine go back to the alley to test McKeen's story. Nick fires shots and Gil runs as McKeen would have. He passes a door and realized there was loud music coming from a bar last night. They get the music going and try it again. Gil hears nothing.
He tells Brass his theory. Brass tells a story about how young McKeen used to invite the new guys out to his place on the lake. Brass made it clear he wasn't on the take and was never invited back again.
Gil remembers how Warrick said Gedda's mole had to be higher up on the food chain. They figure if McKeen saw Warrick's interview he might have had time to frame him but only if he knew exactly where Pritchard was and could count on him not to screw things up.
McKeen unlocks a motel room door. Pritchard is there. McKeen tells Pritchard what Pritchard did. He accuses Pritchard of killing Warrick, tells him the gun got traced back to him. Pritchard says he can blame anything he wants to on him once he's in Mexico. McKeen says it might be easier to kill him there. He points his gun at him.
Grissom and the team tell Ecklie about their theory. He tells them they need more evidence. Sara mentions he would have had to touch the bullets. Ecklie says they've never got prints off a bullet that small.
Catherine watches as the prints are very carefully lifted. There's just enough for a comparison. Its not Pritchard's. Catherine asks the tech, Mandy (Sheeri Rappaport) to step out. She runs it against McKeen's prints. It doesn't match the first finger, but it's positive for the second.
Brass works the phones, trying to get a warrant.
Nick and Archie (Archie Kao) pull McKeen's records. Three calls from a hotel. They go to the hotel, but it's empty, recently vacated.
McKeen and Pritchard drive to Mexico.
Greg confirms Pritchard was in the room. McKeen had rented the room for four days. That makes Pritchard his fall guy, and a dead man. Brass calls McKeen, telling him they think it's Pritchard. They triangulate his phone. Pritchard starts to get suspicious. He pulls out a gun and points it at McKeen. He fires, but McKeen just laughs. He took the bullets out.
Brass and Nick race after McKeen as the rest of the team watches the cell phone signals from back in the lab.
McKeen's signal stops moving. Brass and Nick pull up to a car that has smashed through a guard rail and flipped over down a hill. Nick races to it.
Pritchard is dead inside of a broken neck, and McKeen is gone. Nick follows McKeen's bloody trail into the woods. Brass radios him, but Nick turns his radio off. He approaches McKeen, who lies bloodied and coughing. Nick kicks McKeen's gun away as McKeen spins his story about trying to bring Pritchard in. Nick tells him to shut up, pointing his gun at him. The helicopter pilot describes to Brass what's happening. Brass races to find them.
McKeen starts confessing, saying he did it because Warrick had a big mouth, and he had to shut it. Nick struggles not to shoot him as McKeen tries to taunt him into it. Running through the woods, Brass hears a gunshot. He arrives to find Nick standing over McKeen -- still alive. Nick says he missed. Brass reads McKeen his rights.
At Warrick's funeral, the pews are packed, with the team up front. Grissom speaks, talking about how inadequate their standard "we are sorry for your loss" condolence is. He says Warrick knew how precious life was, living each day as if it was his last. Grissom says his tenaciousness, courage, and loyalty were evident on his last day. Grissom chokes up and says he is going to miss him.