Stark has a rematch with Wayne Callison (Billy Campbell), the serial killer who earlier in the season got off on a technicality by driving the prosecution's star witness to hang herself. This time around, Callison seems to have committed another murder just as he's published a book on how he beat Stark in court.
Though his staff finds the timing odd, Sebastian insists that Callison is a creature of habit, with a need to kill. When his seeming vendetta against Callison gets him dismissed from the case, Stark goes to recently-ousted D.A. Jessica Devlin (Jeri Ryan) for an assist.
The surface drama is high, but it's nothing compared to the final reveal that Stark had been orchestrating Callison's downfall since his improbable acquittal—putting the players in place, keeping his staff in the dark, leaving no trail of evidence. And just after we get a glimpse of his old ruthless ways, we get a moving scene between father and daughter in which Stark is completely vulnerable letting Julie go to New York for a summer study program.
It's been rumored that Jeri Ryan is leaving the show, but the finale hinted that her character might team up with Stark. I hope this happens as she deserves more screen time.