FBI Agent Kate Moretti asks Dr. Daniel Pierce to determine the mental competency of a man being retried for murder. But the trial takes a shocking and unexpected turn when Pierce’s findings question whether the person standing trial is the same person he was six years ago. Meanwhile, Moretti is unpleasantly surprised to discover that the Assistant U.S. Attorney prosecuting the case is her soon-to-be-ex-husband Donnie Ryan.

Pierce and Moretti take on an extraterrestrial case when a woman reports that aliens have abducted her husband. When Pierce and Moretti arrive to investigate, however, they make a startling discovery. Meanwhile, things heat up between Pierce and his real-life girlfriend, Caroline, but his relationship could be jeopardized if he can't get his imaginary girlfriend, Natalie, out of his mind.

When a series of bizarre public murders occur, Pierce realizes that the killer is trying to send a message about inattentional blindness, but Donnie doubts this theory. But Pierce has a trick up his sleeve that can prove his point, and they must scramble to piece together the clues before the clever killer can make any more examples out of innocent victims.

Pierce accepts an invitation to work on a case from a renowned environmental activist concerning a chain of abnormal neurological reactions in a group of young girls. However, upon examining the girls, Pierce discovers that a dark secret is at the root of their ailments. Meanwhile, Moretti questions Pierce’s motives in working on a case without her.