When an axe-wielding, escaped psychiatric inmate drops dead in Castle’s P.I. office, Castle and Beckett’s investigation leads Castle to suspect the victim’s death could be the work of the Antichrist.

Frank, Ray and Ani weigh their options as Caspere’s killer and the scope of corruption is revealed.

Desperate to locate a missing woman with intel about Caspere, Frank meets with Mexican drug dealers; Ani infiltrates an exclusive inner circle, with Ray and Paul keeping close tabs.

Ray and Frank contemplate new life choices. Ani and Paul follow a lead up the coast.