Now that Rosen has discovered the identity of the mole, he must face down the nearly impossible choice of what to do next. Meanwhile, the team takes on their individual family issues: Hicks' son Tyler comes for a surprise visit and John gets to meet Rachel's parents. And Kat gets her first case, tracking a mysterious new street drug that makes users temporarily invincible.

How does one grieve and move on from a terrible loss? Everyone's process is different. Dani's shocking death at the hands of Parish leaves Rosen and the team grasping for lifelines. Presented with his toughest emotional challenge, Rosen struggles to find a way through grief, hiding behind his usual reserve.