The young doctor Alekos returns to his island, after having completed his studies in France, ready to build his life and practice. His mother, however, undercuts his relationship with a poor girl he met at the beach, Xanthoula. The latter lives with her grandfather, "Uncle-Christos", who used to be a sponge-diver but is unable to work anymore. Alekos' mother wants her son to marry the only daughter of Miltos Perotis, Rena, whom she had helped financially after the death of her husband. But Xanthoula doesn't want to marry Alekos either, not because she doesn't love him, but because she knows she will soon die from a weak heart. So she sacrifices her love and agrees to become the wife of Dimitros, a kindhearted man who grew up close to her grandfather and is now thinking of abandoning the sea and all its miseries. Rena, however, finds out how things really stand and decides to step out of Alekos' life, freeing him to live with Xanthoula and help cure her heart condition.