Dr. Lightman is convinced that one of his former protégé's students is a sociopath connected to a woman's disappearance, but everyone else is skeptical. Meanwhile, Torres and Loker help a high school teacher who thinks he saw an UFO.
An Irish terrorist comes to Dr. Lightman to find out who killed his wife and daughter seven years ago, which reveals secrets about Lightman's relationship with Dr. Foster and his past job working counter-terrorism for the government.
Cal agrees to testify for the prosecution until he learns that his ex-wife is representing the innocent defendant: a beautiful younger woman accused of killing her much older, and extremely wealthy, husband.
Dr. Lightman helps Torres's half-sister, who is serving time in a juvenile facility, after an fellow inmate who asks for her help is killed. However, Torres is not convinced that her sister can be trusted.
The Lightman Group discovers that a governor's staffer who was killed during a rally right before the election may have been the target all along to protect a cover-up, and Clara might be lying to protect somebody on the inside.
The FBI investigates the murder of an illegal underground fighter, but Dr. Lightman tries to conceal his relationship to the event. Meanwhile Dr. Foster finds out discovers that her new boyfriend may have a big secret.
The Lightman Group helps a father find his daughter, who left home and became a porn actress, but Cal soon suspects that he's keeping something from him. Meanwhile, Eli and Ria compete for a promotion.
The Lightman Group is hired to examine police profiling techniques in the wake of an incident involving Wallowski, and Internal Affairs attempts to leverage Lightman's relationship with Wallowski to get him to incriminate her.
Dr. Lightman helps a woman with early-onset Alzheimer's Disease uncover a traumatic memory from her past, and in the process discovers that there may be an "Angel of Death" working in her health care facility.