World-weary heiress Celia Barrett (Bennett) impulsively marries a stranger, architect Mark Lamphere (Redgrave). The newlyweds have a blissful honeymoon until a harmless prank by Celia (locking Mark out of her bedroom) evokes a strange response from Mark. He leaves her in the middle of the night - apparently in response to an urgent business telegram - but Celia soon learns that there was no telegram.
Her worries are temporarily alleviated when Mark invites her to join him at the Lamphere family home, but his inexplicable mood swings continue and make her unsure of whether she has married wisely. To add to her concerns, Celia finds out that Mark already has a son from a previous marriage, that the last wife died under Mark's care, and that people suspect Mark of marrying Celia to bail him out of his precarious financial position.
Things only become worse once she learns that Mark likes to "collect" rooms where murders have been committed by recreating them from their original material. There are seven of these rooms, of which Mark is happy to exhibit six. But he insists on keeping the seventh permanently locked. Celia begins to fear that the seventh room contains a dangerous secret from her husband's past that he daren't reveal...
- All Girls Want Bad Boys: Played With. Celia has an unconventional side and is drawn to Mark's unusual ways. But she is genuinely alarmed by his sudden mood swings and dark secrets.
- Antagonistic Offspring: Mark's son, David. Not to Celia (as one would normally expect), but to Mark.
- Art Shift: Mark's Inner Monologue about his guilt is filmed as a courtroom scene in which Mark acts as both prosecutor and defendant in front of a faceless judge and jury.
- Big Damn Heroes: Mark when he goes back inside the burning house and carries out an unconscious Celia to safety.
- Big Fancy House: The Lamphere family home. But it's "mortgaged to the hilt."
- The Blue Beard: Mark's last wealthy wife, Eleanor, died under his care. He also "collects" rooms where murders have taken place, especially where husbands have killed their wives.
- Brainy Brunette: Celia.
- Collector of the Strange: Mark "collects" rooms where murders have been committed.
- Creepy Housekeeper: Miss Robey, Mark's secretary, has an unvaryingly stony expression and wears a scarf at all times to hide her disfiguring facial scars.
- Dark and Troubled Past: It is Implied that something traumatic happened in Mark's childhood which turned his love for his mother to hatred and made him unbalanced, and caused his first marriage to fail. Ultimately Subverted. The incident that traumatised Mark was a mundane prank played by his sister Caroline, which Mark wrongly attributed to his mother.
- Epiphany Therapy: The revelation of who locked him up as a child brings Mark out of his murderous rage.
- Exact Words: Poor Celia gets a nasty shock when she realises that when Mark said that he likes collecting "felicitous" rooms, he did not mean "happy" ones.
- Foreshadowing: The female psychology student's comment that murderers needed to be psychoanalysed.
- Caroline and Celia's conversation about how, as a child, Mark was "besides himself" when Caroline had locked him once for a prank.
- Hollywood Fire: The one from which Mark rescues Celia at the end and thereby redeems himself in her eyes.
- Love at First Sight: Both Celia and Mark claim that this has happened to them.
- Love Makes You Evil: Miss Robey is driven to attempted murder out of her frustrated love for Mark.
- Mommy Issues: Mark had a troubled relationship with his mother, and in fact with every other woman in his life.
- Mood-Swinger: One moment Mark is kissing Celia passionately and the next moment he looks like he positively loathes her.
- Mr. Fanservice: Michael Redgrave is shown once in his undershirt and once in the shower. And that's about as much as you can expect, given The Hays Code.
- Not-So-Harmless Villain: The viewer is led to believe that Miss Robey is a Red Herring Mole, especially after her secret is revealed halfway through the film. However, later, it becomes apparent that Miss Robey is prepared to kill for revenge.
- Parental Abandonment: Averted. Contrary to Mark's long-held beliefs, his mother did not lock him up and leave for the theatre with another man. It was his sister Caroline who locked him up.
- Pet the Dog: A literal example. One of the reasons Celia can't give up entirely on Mark is that she sees him bring home a hurt dog and bandage his leg.
- Plucky Girl: Celia may be "bone lazy" but she won't just sit there and wait for her husband's Dark and Troubled Past to catch up with her.
- Single-Issue Psychology: All of Mark's issues can be traced back to one event in his childhood, when he was locked into a room by his sister Caroline and believed that his mother had locked him in.
- Shout-Out: Miss Robey is a shout-out to Mrs Danvers from Rebecca (1940).