Eric McCormack Eric McCormack

As the exclusive video clip below shows, Perception's Daniel Pierce (Eric McCormack) is about to experience the mother of all hallucinations when his deceased mama Margaret (Poltergeist's JoBeth Williams) pops in for an unexpected visit. As usual, the timing of Pierce's vision is not ideal, coming as the neuroscientist is in the midst of trying to solve a case involving a cancer patient. But working alongside Margaret will ultimately force him to come to terms with lingering guilt over his mother's treatment.

The episode, "Neuropositive," airs Tuesday, Aug. 6, at 10/9c on TNT.

Subscribe to TV Guide Magazine now!