Twelve-year-old budding scientist Lucy Lavender loves exploring. After Dad dies, Mom pieces jobs together and struggles to provide a home for Lucy. When Mom is offered a job managing a set of vacation cottages in Sea Rock Cove, the small coastal town where Dad grew up, Lucy hopes this is her chance to have a home and pursue her dream of becoming a marine biologist. On Lucy's first day at her new school, she is excited to take a field trip to Sea Rock and see Dad's beloved sea stars. When Lucy learns the sea stars have a wasting disease and are dying, she is devastated and becomes determined to save them. But as Lucy gets involved with the people of Sea Rock Cove, she learns there is a lot more beneath the surface of the town than just the sea stars at low tide.