McGarrett is told that his mother Doris had gone rogue during an unsanctioned undercover mission and killed her partner in Mexico. Agent Coen wants McGarrett to fly to Colombia then head up alone to Mexico to bring back Doris and take out cartel head Carmen Lucia Perez. Doris had infiltrated Lucia's operation. He tells his Five-0 team that he has to do this alone, with Junior his backup if needed. DEA Agent Mateo Dias is McGarrett's contact in Colombia. They drive through a suspicious Colombian police checkpoint. Dias is shot and killed and their vehicle flips and blows up but McGarrett escapes into the jungle. McGarrett hops a plane in Panama. Eight weeks later, Junior tracks down Steve in Sinaloa using satellite footage. He talks Danny into letting him go to help McGarrett. Steve confronts Doris, who urges him to leave her alone. She admits her mission had gone sideways but physically refuses his offer to help her escape. McGarrett discovers Junior is in Sinaloa. Steve has put together a team of former SEALs and weaponry to extract an unwilling Doris. They crash a meet Doris is at, blowing up a series of explosives to create chaos and cover. Doris shoots a man sneaking up on McGarrett. Doris tells Steve she's looking for a payday, to get out of her CIA life. Lucia shoots McGarrett while he pleads with Doris. Lucia holds Doris hostage to get Steve to drop his weapons. He admits he's her son. She stabs Doris, then Junior shoots and kills Lucia. Doris dies. McGarrett's team comes for him and Doris and Lucia's bodies. Doris had set up accounts in Zurich for herself and her children. Danny comes to Washington to be with McGarrett, and they wax philosophically about life.