Sam, (voiced by Pamela Segall Adlon) unable to sleep due to a fear of the darkness that fills his room, is inspired by an issue of his favorite superhero comic, Pajama Man, to take matters into his own hands. Journeying into his closet with his purple Pajama Sam mask, Signature-Edition, All-Metal Pajama Man Lunch Box (often known as the Portable Bad Guy Containment Unit), and his Illuminator Mark 5 Jr. Flashlight, Sam tumbles down into the Land of Darkness and is soon stopped by a group of trees acting as customs. After freeing himself, Sam goes on an adventure to reclaim his lost equipment. He befriends a boat named Otto and a mine cart named King, who help Sam throughout his exciting search. After a quest spanning a river, a lava-filled mine, and Darkness's house, Sam goes to confront Darkness.