Recently deceased, a white-sheeted ghost (Casey Affleck) returns to his suburban home to console his bereft wife (Rooney Mara), only to find that in his spectral state he has become unstuck in time, forced to watch passively as the life he knew and the woman he loves slowly slip away. Increasingly unmoored, the ghost embarks on a cosmic journey through memory and history, confronting life's ineffable questions and the enormity of existence.