In the final book of the Haunting with Louisa trilogy, Dee and her best friend Louisa, a ghost from the 1890s, find Louisa's fourth relative so that she may rejoin her family. In the process, they stumble on a lobster-stealing ring and solve the mystery of the Ghost Ferry.
Summer has arrived at Harbor Island, alongside the multitude of tourists. Louisa argued that Dee should spend more of her time making live friends. Dee would rather help Louisa find her family. Rumors of a ghost ferry drew her attention to protecting Louisa from being whisked away. Was there truly a ferry that came for lost souls, or were the lights in the fog something more sinister?