Republic of Doyle’s season finale will feature Paul Gross, who has been on the entertainment scene since his role on Due South in the early ’90s. The episode he’ll appear in, titled Family Business, airs Wednesday, April 6. He’ll play the unstable John Crocker, a former police partner of Jake Doyle (Allan Hawco) from their days together on the force. Crocker has returned to St. John’s to get some help from his old buddy Jake. Things turn dark when it quickly becomes apparent that Crocker is more than capable of backing up the awful things he threatens, which puts the entire Doyle family in jeopardy. *cue foreboding music*