Fredrik is a lustful lawyer living a platonic marriage with a virginal wife, Anne. Henrik, his son by his previous marriage, is after Petra, the family maid. Fredrik's old mistress, an actress named Desirée, is in town, and he goes to see her. But now she has a new lover, the fierce Count Malcolm, who in turn has a fierce wife, Charlotte.

All are invited to Desirée's mother's estate for a weekend party. After flirting here and there Petra ends up in a hay stack with Frid, the groom. Charlotte tries to seduce Fredrik, hoping to get him back from Desirée. Anne, Fredrik's wife, discovers a strong attraction for Henrik.

The jealous count, discovering Fredrik with Charlotte, challenges him to a game of Russian Roulette, which Fredrik loses. Fortunately, the gun is loaded with blanks. Anne runs off with Henrik, her step-son, and Fredrik discovers he has been in love with Desirée, and she with him, all along.

"Bergman's first major success, inspiration for both Stephen Sondheim's A Little Night Music and Woody Allen's A Midsummer Night's Sex Comedy, this enchanting comedy of manners assembles a team of couples, ex-couples and would-be couples, and puts them through their paces in a game of love at a country house party during one heady midsummer weekend in 1900. Ruthless towards its characters' amorous pretensions, but extending a kind of ironic tenderness when they get hoist with their own petards, it is a wonderfully funny, genuinely erotic, and quite superbly acted rondo of love. Dig too deeply and it disintegrates, but its facade—decked out in elegant turn-of-the-century settings and costumes—has a magical, shimmering beauty."

"Nowadays I let my characters look after themselves. In the old days I used to do a lot of building, planned my script, steered (as it were) people's fates, guided their footsteps. But now they have to look after themselves, and I let any characters come into the picture who want to and then float out again. I suppose I've a much freer relationship to what I'm doing. The climax of my 'constructions' is Smiles of a Summer Night, which is based on a play by Marivaux, in the classical 18th-century manner. But when I'd done all that, it didn't amuse me any longer. It's the sort of thing one makes use of to train oneself; to try out one's capacities."