What Have You Done to Solange?

In London, the Italian gym teacher Enrico 'Henry' Rosseni is having a love affair with his eighteen year-old student Elizabeth, who is the niece of the owner of the Catholic school where he works and she studies. His estranged wife, Herta is the Music and German teacher. One day when Enrico and Elizabeth are in a boat in a grove, she sees a man hunting down a woman. Enrico believes she's making it up, but the next morning, he learns a teenager was murdered in the river bank in the grove. Inspector Barth goes to the school since the victim Hilda studied there and soon, Enrico is the prime suspect, though Elizabeth could give an him an alibi. When a second student's murdered, and then so is Elizabeth, Enrico decides to investigate, and teams up with Herta to find the of the mysterious Solange, but what might have happened to Solange?