France, 1920s. In a seaside hotel, a magic show entertains idle guests.

Marta, a young woman unhappy with her jealous husband, agrees to take part in a disappearing act, taking advantage of the opportunity to disappear for good.

In response to the husband's demand for his wife's return, the magician puts a box in his hands and tells him she's inside.

But he mustn't open it unless he has absolute faith in her, or he'll make her disappear forever. Charles begins to have doubts.