The poem describes a dream-like encounter between the speaker and a mysterious woman. In the dream, the speaker wakes from a kiss only to search for the woman along rivers and the seaside, catching glimpses of her in unusual places like a sand castle or underwater. They have a conversation beneath the sea with the moon overhead. The next night, the speaker's chest escapes through a broken seawall, and he finds the woman knitting on the other side. They greet one another before the speaker awakens as the sun rises.