After offending the powerful pastor of a cult, Mari McGavin has to flee with her six-year-old son. With no money and no place else to go, she returns to the tiny Maine island where she grew up--a place she swore she'd never see again. There Mari runs into her lifelong friend Harry Richardson, one of the island's summer residents, now back himself to sell his family's summer home. Mari and Harry's lives intertwine once again, setting off a chain of events as unexpected and life altering as the shifts in climate affecting the whole ecosystem of the island...from generations of fishing families to the lobsters and the butterflies.