Allsion is asked by Devalos to help some of his friends find their missing daughter, but encounters conflicting evidence of who is responsible for her disappearance. Meanwhile, Lynn and Scanlon encounter relationship trouble.
Allison wakes up under a freeway overpass, not knowing where she is or how she got there. Her lack of recent memory causes her to start thinking she may have killed someone with her car.
The first family, including daughter Olivia (Sprague Grayden), face painful circumstances; Chloe has words with Janis Gold; and Jack and Agent Walker track leads, trying to prevent another terror attack.
Allison's paranormal peeks concentrate on several killings---all of which are witnessed by an apparent ghost. Elsewhere, Ariel partners with her school crush in health class, and together they care for an artificial baby. But the assignment has a bizarre effect on Ariel: She feels drugged whenever she holds the baby.
Devalos' friend's sister is murdered and Allison tries to help solve the crime. Her dreams don't seem to make sense though, as they keep implicating the friend's first husband, who died two years ago, as the murderer.
In the fourth season finale, Allison tries to help a young couple who thinks their house is haunted, but her efforts result in murder. Meanwhile, Meghan Doyle tries to sell her controlling interest in Joe's invention and Joe tries to save his own stake in it. An unexpected situation occurs between Devalos and Tom Van Dyke and the outcome effects the election for district attorney.
Allison has dreams that help Scanlon in his search to find out who killed a wealthy local drug dealer. Allison and Scanlon are dumbfounded when Allison's dreams lead them to a severely impaired man with a bullet stuck in his brain. Meanwhile, Joe's partnership with Meghan Doyle is put in jeopardy.
Allison meets Meghan Doyle, Joe's new business partner. Meanwhile, her old car stops working and Joe surprises her with a nice looking used car. The car ends up being the center of a horrible unsolved crime though.
Allison has visions of a friend of Scanlon and Lynn DiNovi dying in a home mishap. This causes her to struggle with connecting some recent "accidental" deaths, consequently putting her own health in jeopardy.
When Joe presents his new solar power-based invention to an investment firm, he piques the interest of venture capitalist Meghan Doyle. Meanwhile, FBI profiler agent Edward Cooper claims his return to Phoenix is to track down another serial killer, but Allison's dreams tell her otherwise.