The Polarizing Express (S05E14)

Shawn's antics cause evidence to be thrown out in the high profile prosecution of a known crime lord named Czarsky, resulting in the dismissal of the entire case and the firings of not only the Psych agency but also of Henry as their liaison. After Henry wonders to Shawn what life would have been like in Santa Barbara if he had never returned, Shawn travels through a series of dreams which answer that question and aid him in discovering a new way to bust Czarsky for good. (Prime Video)