Dixon 'Dix' Steele (Humphrey Bogart), is a hard-drinking bad-tempered hollywood scriptwriter. When his agent (Art Smith) gives him a novel to read with a view to adapting it for the screen, Dix, too tired to read the book himself, asks hat-check girl, Mildred Atkinson (Martha Stewart) who has read the book, to come home with him and explain the plot. When the girl's murdered body turns up the next day, the police suspect Dix: his only alibi is new neighbour Laurel Gray (Gloria Grahame) who saw Mildred leave Dix's apartment the night before. Dix finds out that Laurel is an struggling actress, he begins to fall in love with her: happier, he's inspired to renew his writing work. But policemen Brub Nicholai (Frank Lovejoy), and Captain Lochner (Carl Benton Reid) sew seeds of doubt in Laurel's mind, and she begins to suspect that Dix is not so innocent. A furious Dix loses his temper and beats up a motorist after a minor traffic incident. Laurel begins to fear for her life. Even if Dix's innocence can be proved, will their love survive?