A harbour tavern provides the setting for a drama about lost love and the irresistible call of the sea: Old Peter Petersen runs the inn "Zum schwarzen Walfisch" (The Black Whale). His son Martin is in love with Fanny, the daughter of fishmonger Jürgens. Against the will of his father, Martin leaves Fanny and his old life behind and enlists as a sailor. Fanny, who is expecting Martin′s child, finds solace in grumpy, but kind-hearted Petersen. Petersen′s widowed friend Pannies also takes care of the girl, and eventually the two get together. But when Martins returns home one day, he threatens to destroy Fanny′s newfound family.