After a drunken binge on the San Pablo waterfront, longshoreman Bobo fears he may have killed a man. In his uncertainty, he takes a job on an isolated bait barge. That night, he rescues lovely Anna from a watery suicide attempt and installs her on the barge. But Tiny, Bobo's longtime pal and parasite, hopes to drive Anna away before domestic bliss tears Bobo away from him; the still unsolved murder may be just the wedge Tiny needs. There's fog on the water and evil brewing...