The 1964 Disney film of the same name, starring Haley Mills, is very different from the 1962 book. In the movie, Nicola Ferris is renamed Nikky and de-aged by about ten years, Mark is a suspected jewel thief instead of an innocent tourist, and there's a cheetah. Yes, a cheetah. On a boat.
This movie was, I believe, my very first exposure to Mary Stewart. I watched it as a child, but didn't read the book until recently. Frankly, I don't see why so much was changed. The Moon-Spinners is a strong book, populated with Stewart's usual blend of bold female characters, lush scenery, suspense, and believeable plot twists.
Nicola Ferris is a very unimportant clerk at the British Embassy in Athens, Greece. She is fairly fluent in Greek, and loves the country. She talks her cousin into taking a week-long vacation in Crete, where they'll meet and then take a cruise. Arriving a day early, Niccola stumbles across Mark, a man who's been shot, his Greek guide Lambis, and their tale of violence and intrigue. Being completely unlike me, Niccola takes charge of the situation, cleans the man's wound, and promises to help him find his younger brother, Colin, who was kidnapped by the people who shot at Mark.
When Niccola's cousin Frances arrives, Niccola tells her everything and explains why she can't go to the police... in such a small village, the police might be involved, or even corrupt, and such action might kill Colin. Frances doesn't believe that Colins is alive, but promises to help Niccola in any way she can.
This is a very solid and compelling book, exciting, with an open-water chase scene and a romantic angle that isn't overly emphasized. Niccola is naive and soft hearted, but she isn't stupid. She's confident and able to bluff her way out of danger.