The Treasure of Vaghia

The Treasure of Vaghia (Greek: Ο θησαυρός της Βαγίας) is a 1969 novel by Greek author Georges Sari. It is her first novel and is partially autobiographical. A television series based upon the book aired on Ellinikí Radiofonía Tileórasi in 1984.
Plot summary.
This summer a group of children spend a wonderful holiday on the Greek island of Aegina. The arrival of a beloved French friend, a young psychiatrist working in Paris, will bring, apart from joy, a mission. To find a hidden treasure that could help a falling friend drive away his demons.
A novel of strong emotion, full of adventure and rich descriptions, where the author perfectly recreates the particular atmosphere of children’s summertime on an island.