Colbert on Monday revealed that the film will be based on “Fogs on the Barrow-downs,” the eighth chapter of The Fellowship of the Ring, where Hobbits are trapped by a Barrow-wight in an unnatural fog. The story also includes a fan favorite character omitted from the previous films, Tom Bombadil. The movie will be derived from chapters three through eight of Tolkien’s landmark book.

The Lord of the Rings: Shadow of the Past is set 14 years after the passing of Frodo. Sam, Merry and Pippin set out to retrace the first steps of their adventure. Meanwhile, Sam’s daughter, Elanor, has discovered a long-buried secret and is determined to uncover why the War of the Ring was very nearly lost before it even began.