Roland Deschain accessed Dean's mind through a door - marked "The Prisoner" - standing on the shore of the Western Sea, and drew him from New York City in 1987 into All-world. After helping Dean fight through his heroin addiction, Roland trained him as a gunslinger, and Dean accompanied Roland and Susannah Holmes along one of the Beams toward the Dark Tower. He helped Holmes and Roland to draw Jake Chambers into All-world, and traveled with them to Lud, where the four boarded a monorail bound for Topeka, Kansas.
Dean managed to outriddle Blaine the Mono, thereby saving the lives of his ka-tet, and traveled through Topeka toward Emerald City where he confronted the Tick-Tock Man and the man in black. The ka-tet pressed on, traveling to Calla Bryn Sturgis, where Dean helped the townspeople to fight the androids that had been assaulting their town.
Dean was later killed during the Battle of Algul Siento.