Marie is a student at the Opera Ballet School, and she observes a young timid student, Henrik, who seems to admire her. During summer vacation they meet on a boat trip, fall in love, and spend wonderful weeks together. Henrik dies in an accident, however, and Marie falls into an affair with her old uncle, Erland.

Ten years later, Marie has become a prima ballerina. Before an opening night she receives Henrik's diary. After quarrelling with her present lover, David, a journalist, she travels to the summer cottage where she recalls the time with Henrik.

She returns to the ballet and gives the diary to David that he may understand her better. The memories have purged her life of the darkness it has been in these ten years, and she now looks forward to life with David.

"This early Ingmar Bergman film is about the loss of love: a tired ballerina of 28 (Maj-Britt Nilsson), who has ceased to feel or care, is suddenly caught up by the memory of the summer when her life ended. We see her then as a fresh, eager 15-year-old, in love with a frightened, uncertain student (beautifully played by Birger Malmsten), and we watch the delicate shades of their "summerplay," interrupted by glances at adult relatives, as Bergman contrasts decadence and youth, corruption and beauty. In the early part, an old woman appears for just a moment in a road, walking—and this image, like the croquet game in the later Smiles of a Summer Night, seems to be suspended in time. Bergman found his style in this film, and it is regarded by cinema historians not only as his breakthrough but also as the beginning of 'a new, great epoch in Swedish films.' Many of the themes (whatever one thinks of them) that Bergman later expanded are here: the artists who have lost their identities, the faces that have become masks, the mirrors that reflect death at work. But this movie, with its rapturous yet ruined love affair, also has a lighter side: an elegiac grace and sweetness."

"For me Summer Interlude is one of my most important films. Even though to an outsider it may seem terribly passé, for me it isn't. This was my first film in which I felt I was functioning independently, with a style of my own, making a film all my own, with a particular appearance of its own, which no one could ape. It was like no other film. It was all my own work. Suddenly I knew I was putting the camera on the right spot, getting the right results; that everything added up. For sentimental reasons, too, it was also fun making it."

Jean-Luc Godard: "Bergmanorama"

Philip Strick: "Film Notes"