Muldoon is tasked by his Aunt Kay to find the person behind his uncle, Mr. O's murder. When Joe Patton, the head of the west side Irish Mob, discovers who killed Mr. O, he demands answers. Patton's son, Rusty, next in line to take over the Irish Mob, attempts to clean up the mess. Mr. O's son, Sean O'Bannon, also a Public Morals officer, starts a romance with best friend's Duffy's sister, Deirdre. The new cop in Public Morals, Shea, also gets a taste of the fun side of working in Plainclothes when Bullman takes him to a private, illegal casino.