Andy McNally
停職結束後，Andy急切想要回到工作崗位，並且再次和Sam Swarek合作。從上一季開始她的人生有急遽大轉變。Luke Callaghan已經被調離第15分隊，而Andy被獨自調開，她不顧一切想要把工作和個人生活分離，不想再犯同樣的錯誤。
Having completed her suspension, Andy McNally is eager to get back to work and to fellow officer Sam Swarek. Life has changed since last season. Luke Callaghan has transferred out of 15 Division, Andy has settled into her new loft alone, and she’s hell bent on not letting her personal life interfere with her job.
Traci Nash
比起其他的事物，Traci想要成為受訓警探，也就是跟在她導師和愛人Jerry Barber的身旁。所以當她獲得這渴望已久的職位時，她人生的一切似乎都邁進了正確的位置，包括她的感情、事業和私生活等等，全都一帆風順。
More than anything right now, Traci wants to be a Detective in Training. Which means working alongside her mentor and lover, Jerry Barber. So when she wins the coveted rotation, everything in her life finally seems to click into place; her relationship, career and personal life are all intact and on track.
Dov Epstein
Dove Epstein, 15分隊的熱血菜鳥，全心全意投入工作。兩年過後，他獲得了眼界和自信，他完全掌握大局和自己的人生。他的女朋友是個拆彈專家。他最好的朋友是位同事，而在街上出身入死變成他的習以為常的事。但今年生活到處出了狀況，當Dov被迫要在工作上做出致命分裂的決定。從那一刻起，開始威脅到他之前努力所獲得的東西。
Dov Epstein, 15 Division’s live-wire rookie, has fully embraced his life as a police officer. After two years on the beat, he’s gained both perspective and confidence; he’s at the top of his game and in control of his life. His girlfriend is a bomb technician, his best friend and wingman is a fellow officer, and life on the street has become second nature. But this year, life attacks from all angles when Dov is forced to make a deadly, split decision on the job -- and when the fallout from that moment starts to threaten everything he’s worked so hard to achieve.
Chris Diaz
15分隊的保守小鎮男孩準備要打破他的之前的性格。決定擺脫之前墨守陳規，看著準則行事的作風。他終於和前女友也是同事Gail Peck和好，成為朋友。但當Gail的舊情人Nick Collins回來後，加入分隊並且和重新和Gail舊情復燃，Chris情不自禁注意到，並且帶有報復心態試圖和每位身旁的女生約會。
15 Division’s resident small-town boy is ready to break out of his old persona. Gone are the days of sticking to the manual - both on and off the job. He’s finally friendly with ex-girlfriend and fellow Officer, Gail Peck; but when her old flame, Nick Collins, joins the Division and strikes up a relationship with Gail, Chris can’t help but take notice and react in kind… by dating every girl who comes his way.
Gail Peck
由於經歷過家庭壓力和對於事業的嫉妒心，Gail準備好要創下一片天，只是她得先清楚自己想要什麼。但當15分隊新人報到時，她的舊情復燃了，Gail發現自己還有依戀，心中埋藏已久的感情和自我懷疑又浮出心頭了。
Having weathered the storm of family pressure and professional jealousy, Gail’s ready to make her mark - if only she knew what she wanted to do. But when a past flame shows up as 15’s newest rookie recruit, Gail finds herself rehashing an old heartbreak - uncovering deeply buried feelings of heartache and self doubt.
Nick Collins
15分隊的新人，Nick Collins期待他日後成為警察的日子。從阿富汗服役回家後，Nick希望能夠放下部隊生活，重新來過。但當他成為15分隊的新成員後，他發現自己將會和舊情人Gail Peck一起共事。
New to Division 15, Nick Collins is looking forward to starting his new career as a cop. Having recently returned home from serving in Afghanistan, Nick is looking forward to putting his military career behind him and starting over. But when he becomes 15 Division’s new rookie, he finds himself working alongside his ex-flame Gail Peck.