After the death of his older brother Joe (Kyle Chandler), Lee Chandler (Casey Affleck) is shocked to discover that he has been appointed sole guardian of his nephew Patrick (Lucas Hedges). Lee leaves his current job and returns to the village of Manchester-by-the-Sea, filled with anxiety, to care for the spirited 16-year-old Patrick. He is also forced to confront his past, which has separated him from both his wife Randi (Michelle Williams) and the community in which he was born and raised. Lee and Patrick, who share the bond of the one person who held their family together, both struggle to come to terms with life in a world without Joe.