The following contains spoilers for Walker Season 3, Episode 15, "False Flag, Part 2," which debuted Thursday, March 30 on The CW.

Walker's FBI agents and Texas Rangers were unable to prevent the domestic terrorist group Grey Flag's devastating attack. Now in the aftermath, Cordell Walker has barely survived and is accused of helping the organization due to being held captive by them in the Walker Season 3 premiere. With the evidence mounting against him, Walker sets out to clear his name and track down those truly responsible for the heinous assault on the Lone Star State.

Captain Larry James takes point on a press conference detailing Grey Flag’s attack on the mayoral event. The mayor is in critical condition and seven people have been killed, largely FBI agents and investigative reporter Julia Johnson. Because of Grey Flag’s funding the Walker family’s horse therapy program and Walker’s independent research into Grey Flag -- including confiscated C4 from the organization -- he becomes the subject of an FBI manhunt. James, Cassie Perez and Trey Barnett are all skeptical as the FBI canvasses the Walker family ranch and pores over the Texas Ranger’s assets. Cassie tracks Walker to a local gas station where he is siphoning gasoline; he shares why he ran from the authorities.

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Walker Captain James (played by Coby Bell) briefs the Walker family

Walker reunites with Geri Broussard, urging her to find a way to communicate to his family that he’s okay, only to pass out abruptly in Geri’s backyard before he can continue his escape. Geri brings Walker inside her home to help him recover, but is upset as Walker tells her about his complicated dynamic with Clay Cooper. Aware that the ranch’s phones have been tapped by the FBI, Geri relays a coded message to Stella about her whereabouts and Walker’s condition, with Bonham understanding what Geri is trying to say.

Trey and Cassie’s investigation links Grey Flag to a local billionaire tycoon who has an airfield on the outskirts of Austin, realizing Grey Flag leader Kevin Golden is on his way there to make his escape. Frustrated that he was unable to kill the mayor and after being chewed out by his billionaire benefactor, Kevin murders the other man on the spot and prepares to steal one of his private planes. On their way to intercept him, Trey and Cassie privately vent their raw feelings about Kevin’s betrayal. Cassie is angry that Trey pushed her into a relationship with Kevin while Trey feels guilty about his role in Grey Flag’s terrorist attack.

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Walker Kevin Golden (played by Jake Abel) tries to escape in a garage with a yellow sportscar

Based on Geri’s message, Bonham links up with his son. The two men launch an attack on the remnants of Grey Flag at the airfield, engaging in a fierce firefight. While Bonham secures the perimeter, Walker confronts Kevin in the hangar alone, revealing that he learned Kevin was targeting him and his family because Cooper is his older brother, and he blamed Walker for losing Cooper in Afghanistan. Cooper saves Bonham from some of Kevin’s gunmen outside before facing his brother, with Kevin visibly shocked that Cooper was alive all along.

Cooper apologizes to Kevin for abandoning him for decades and tries to convince him to and turn himself in for all he’s done. Incensed, Kevin tries to shoot Walker, but Cooper takes the bullet for his old friend. Kevin tries to take off in a small plane only for Walker to intercept him with a motorcycle. As Kevin stops to finish off Walker, he is shot and killed by Cassie, with the rest of the authorities arriving on the scene. The resulting investigation and testimony from a recovering Cooper clears Walker’s name, but Cassie and Trey’s friendship remains seriously ruptured. Cassie feels Trey betrayed her trust in him as the Grey Flag ordeal comes to an end.

Developed for television by Anna Fricke, Walker airs Thursdays at 8:00 p.m. on The CW, with episodes available to stream the following day on the CW App. Walker returns April 27.