Following a lead in the kidnapping case of Mia Westlake, Bosco and his CBI unit converge on a house in a run down neighborhood in Oakland. They expect the house to be empty but see that the lights are on inside. They break down the door with their guns drawn and find Lisbon and her CBI unit investigating a corpse found at the same house. The corpse is identified as Colin Haymer, a kidnapping victim from 3 years ago. The family paid the ransom, but their son was never returned to them. Minelli agrees with Lisbon and Jane on the coincidence of the house coming up in both the Westlake and Haymer kidnapping cases and wants Bosco and Lisbon's teams to work together on the outcome. The $3.75 million ransom demand for Mia is received and the specific amount requested leads Jane to suspect there's someone working on the inside. Jane's lost interest in the corpse preferring to pursue the current kidnapping investigation which Bosco reluctantly agrees to. Back at CBI a lead from the abandoned house where this all started takes Rigsby, Van Pelt and Agent Hicks knocking on doors at an Oakland apartment complex looking for "Deezer", the leader of the Crazy Hill Gang who were responsible for Colin Haymer's kidnapping. One resident surprises Van Pelt shooting her twice in the chest, but her Kevlar vest absorbed the shots. Rigsby and Hicks pursue the suspect ending with Rigsby killing who is soon identified as Diane Zaranski aka "Deezer", Colin's girlfriend who the SFPD suspected of working for the gang that abducted him 3 years ago. Bosco comes around on Jane's suspicion of someone working on the inside and participates in Jane's plan that flushes out Mrs. Kent, Verona and Duncan Westlake's nanny. Tracing the last call Mrs. Kent made to the kidnappers from her cell phone, they rescue Mia Westlake. With a new respect for Jane, Bosco gives Jane his Red John file and asks for his unique perspective.