Twelve-year-old twins Colm and Mal might look identical, but they’re different in just about every other way. The boys soon discover that their new apartment building, Brunhild Tower, is full of strange quirks: a mysterious Princess who warns them not to wander the building at midday, eerie sounds coming from the walls, and an elevator that’s missing a button for the thirteenth floor. Then one afternoon, that button appears, catapulting the brothers and their inquisitive new neighbor, Tamika, into a parallel dimension and a twin building stuck in time, where the spirits of all the former residents of Brunhild Tower live on, trapped by an ancient curse. Now, Colm, Mal, and Tamika must race against time to solve the mystery of the phantom tower—or risk spending an eternity as ghosts themselves.