The team attempt to uncover a CIA mole who is endangering the lives of operatives; during the investigation the CIA takes over the Behavioural Analysis Unit offices to prevent further electronic leaks which puts further pressure on the team.
A college student becomes a target after her work as an online porn star is discovered by her classmates.
The murder of a high school mean girl draws Castle back to one of his many alma maters, where he is giddy to learn that the evidence points to a surprising perpetrator.
The team pursue a drug dealer and child pornographer after an agent is killed in an explosion at a meth house. The case stirs personal memories for Charlie, who is reminded of a girl he knew as a child whom he believes was abused.
Addison cannot stop thinking of Pete; Violet's ex visits the clinic and Cooper is not happy to see him; Naomi and Sam's daughter secretly seeks Addison's medical advice.
