In the wake of the groundbreaking success of 2017's IT, the highest-grossing horror movie of all time, and its subsequent sequel, Welcome to Derry is based on the five interlude chapters from Stephen King's iconic 1986 novel and is intended to play out over the course of three seasons, set in 1962, 1935, and 1908, respectively. The project, which was developed by Muschietti alongside his sister, Barbara Muschietti, and co-showrunner Jason Fuchs, will explore the origins of Pennywise (with Bill Skarsgard reprising the role) by turning back the clock in 27-year intervals to historical periods that coincide with the cycles in which It was awake and actively preying on the children of Derry, Maine. The series sticks with the timeline of Muschietti's movies rather than King's book, meaning the original Losers Club encounter with It takes place in 1989 rather than 1958, and the final battle in 2016 rather than 1985.