The abduction of a young woman leads the team back to a cold case from 18 years ago, which pushes Isobel to reconnect with her old partner Jake and take another shot at solving one of her first cases at the Bureau.

After a mysterious bioweapon leaves two MTA workers dead and one injured, the team rushes to determine who is behind the attack and the location of their next target. Also, Jubal's past demons begin to surface when the high-pressure case coincides with Tyler's latest health scare.