Boom!

(Part 2) After barely surviving an explosion that destroys her apartment, set by the serial killer, now identified as Scott Dunn, Beckett pushes Shaw's imposed boundaries on her involvement in the investigation, and gets herself removed from the case. But when Dunn kidnaps Shaw to get to Beckett, Beckett takes over the investigation and finds herself relying on Castle's instincts as a mystery writer to save Shaw and herself.