Flashbacks begin most episodes. These flashbacks show that Henry Spencer wished that his son would follow in his footsteps and become a law enforcement officer. In preparation, Henry helps Shawn hone his powers of observation and deduction, often using games and challenges to test him. Each flashback also sets the theme for the episode, based on the challenge Shawn's father presents him.
Shawn originally becomes known as a psychic when, after calling in a tip on a crime covered on the news, the police become suspicious of his knowledge. Theorizing that such knowledge could only come from the "inside", they decide to arrest him as a suspect. To avoid being sent to jail, Shawn he uses his observational skills to convince all present that he is psychic. The interim police chief warns Shawn that if his "powers" are fake, he will be prosecuted. With no choice but to keep up the act, he becomes a psychic consultant to the police. Pretending to have psychic powers allows him to engage in strange and comic behavior as he turns real clues into hunches and otherworldly visitations. He enjoys teasing lifelong friend Gus, a pharmaceutical representative, about his eclectic interests.