Castle worked out that Ben Conrad was a scape-goat, shot by the real serial killer. He was too late to prevent Becket's place being bombed, but she survived, having being in the bath at the time. Shaw's profile and databases lead to a likely suspect, Doherty, actually deceased: the new fake identity. The team stakes his place, but the killer expected them. He gets away, but is identified. Becket is barricaded in castle's home, but the killer captures Shaw. Only Castle manages to think like him and prevent a big bang finale.
—KGF Vissers