The last prisoner (1970)

Dinos, the sole survivor of a group of saboteurs who were exterminated by the Germans for treason, finds refuge in the house of a crippled girl. She hides him in the basement and, falling in love with him, keeps him prisoner without telling him that the war is over, not wanting to lose him. When Dinos manages to escape from the basement, he faces the bitter reality. His girlfriend doesn't care for him, his friends died in the Occupation, and the one who betrayed the group was a fellow soldier. He decides to return to the basement and the girl who really loved him.