After a collegiate women’s rowing team goes missing during morning practice on the river, MPU deduce that their boat was sabotaged. When Kemi finds evidence connecting one of the girls to Irish mob boss, Charlie McGannon, Nikki confronts him as Jason and Mike interrogate a rival Polish mobster who may have intel on the girls location. Meanwhile, Jason explores his fear of commitment with Wayne, who’s now paroled.

When Nikki suddenly goes missing, MPU bands together and discovers that Raina, a criminal who Nikki put away, has escaped and is out for vengeance.

As the MPU struggle to adjust in the wake of tragedy, they are forced to jump into action when a muralist goes missing after painting a piece on a local rooftop; the missing person's mother reveals that he was scheduled to donate his rare bone marrow to his dying brother, who needs surgery within the next 48 hours in order to survive.

When an Army Lieutenant, and the wife of Houston’s old Army buddy, is kidnapped, MPU suspects a Major who the victim had reported for harassing women at the base. However, Jason and Mike learn that the victim and her husband were having marital and financial issues, leading them to uncover a dangerous and deadly weapons trade.

When Violet, a psychiatric patient, escapes her facility, Jason and Mike are shocked to find a letter from Jason and Nikki's daughter Sidney among her belongings. Mike and Jason go to her halfway house, they realize that she has been off her medication for days and are now concerned for her safety. Meanwhile, Helen takes her new relationship to the next level.

An accomplished playwright is kidnapped prior to a local theatre's grand reopening. MPU discovers that the victim and her partner had received a video threat ordering them to shut down the troubled theater, which had previously been severely damaged in a fire decades earlier killing 87, or the playwright will be burned to death. Meanwhile, Jason asks Wayne to track down who's the father of Sidney's baby.

When a young woman is kidnapped and locked away to freeze to death, the MPU suspects her boyfriend or his father might know more than they're letting on. Meanwhile, Wayne uses her connections to try and get a job at the MPU, and Kemi is put in a dangerous situation while on the case.

When a customs broker goes missing, MPU discovers that she is an undercover FBI informant now being forced to transport a little girl over the border to her criminal father. Jason and Mike find a tablet at the girl's last known location, and defying the FBI's orders while working alongside Lt. Gabrielle Bennett, Jason goes undercover in order to rescue both the customs broker and the girl.

When a brewery foreman is kidnapped after arguing with his CEO over safety violations, MPU finds evidence that suggests that the victim was taken by competitors over a stolen beer formula. Also, Bennett’s ex, who is also Houston’s step-son, threatens to make her life hell for interrogating his client without representation.