This 1959 novel begins in a fictional mideastern country. The country is on the brink of revolution, the young prince is planning his escape he entrusts the family fortune in gems to his closest friend to smuggle out of the country. Arrangements are made shortly before the two young men are killed.
Meanwhile, back in England it is the beginning of the summer term at Meadowlands, an exclusive girls' school. Students and staff from all over the world are there, including a princess from the mideast whose cousin/fiance has just been killed. The famous gems have also found there way there. Various unusual occurances begin to take place at the school, strange visitors, unusual behavior among the staff and then murder and kidnapping.
One of the students uncovers part of the secret and decides that she needs outside help so she contacts Hercule Poirot. Poirot, of course, resolves the mysteries both large and small that have been plaguing the school.
There are more characters introduced in this novel than is usual in Christie's work which makes this one of the more challenging of her work to figure out. There are several subplots woven into the action that things confusing as well. This is a departure from Christie's usual 'cozy' stories of village life or house parties. It is more of a thriller than her usual work, some of her most sympathetic characters are killed and Poirot only appears at the end of the novel. Even so it is a very enjoyable mystery and one of my personal favorites.
We are also treated to an update on the Summerhills, old friends from a previous book, MRS. McGINTY'S DEAD. Mrs. Summerhill is a friend of one of the students' parents. Poirot is delighted to hear that although Mrs. Summerhill's house is still disorganized and her cooking is generally deplorable she makes wonderful omelets, a skill that she learned from him.