Erin and her best friend Jacob are excited to visit Erin’s great Aunt Kate on Nantucket Island, and explore the Harbor House Hotel where Erin’s parents used to work. But soon after their arrival, the heirloom lightship basket Erin’s mother had left to her before she died (and which Aunt Kate was keeping until Erin’s 16th birthday) is stolen. Heartbroken over this loss, Erin is determined to find the thief and the only memento she has of her mother.