It's the year 1925 and Autumn Frayley is running from trouble in northern Michigan. Looking for a place to hide, she finds refuge on an old fishing boat and falls asleep. Upon awakening, the young woman finds herself on Little Bear Island where the old lighthouse keeper, Mampy, takes her in. Autumn eagerly learns about what it means to "keep the light" in a charming time when lighthouse keepers were needed to protect ships from peril on the Great Lakes. Learning about the island and its inhabitants is interesting and sometimes amusing, but it becomes evident that not everyone on Little Bear can be trusted. Autumn soon realizes that boat trip across Lake Michigan has now changed her life forever.