Highly respected A.D.A. Jack Buckley, a tough crime-fighter, was murdered. His brother in law, businessman Paul Cho, was blackmailed mysteriously with his use of call girls from 'Danton.' Team Castle discovers it's all about the discreet cyber-pimp business, which also employs Buckley's legal protégée Scarlett Price. While working out who succeeded jailed founder Dan Tonelli, 'cool dad' Castle worries which secret Alexis shares only with Becket.