Five young and ambitious rookie cops continue to navigate the emotional trials and tribulations of their professional and personal lives. After two years on the job, these rookies are well on their way to becoming experienced cops. But at what cost? What price will they have to pay, both professionally and personally, to succeed at their jobs? And how can they stay true to themselves - maintaining their individuality and compassion - along the way? While a new rookie has joined 15 Division -- ex-soldier Nick Collins, who is trying to adapt to civilian policing after serving in Afghanistan -- the rest of the rookies are now entering their third year on the job. They have overcome the sophomore curse: that a little knowledge is a dangerous thing. However this year, the rookies of 15 Division are going to have to learn to be careful what they wish for - and they are going to learn it the hard way.