Fisherman Patrick Hennessey and his wife, Maggie, live an idyllic life with their two children in the remote New England fishing community of Folly Cove on isolated Great Saucauset Peninsula, but Folly Cove has a dark past. On the eve of the town’s 400-year anniversary, a covenant their Pilgrim ancestors made with an ancient evil has come due, and Patrick and Maggie must risk everything to protect their family from a cosmic horror that threatens to destroy them.