When Claire is only seven years old, her eighteen year-old sister Alison disappears and is found dead when their family takes a vacation on a Caribbean island. This book takes place mostly in NYC where Claire, now called Emily, is a young adult working at her first job. By happenstance, she runs into one of the men from the island who was accused of killing her sister, but was not convicted due to lack of evidence. She befriends this man to learn more about what happened to her sister, to the detriment of her own mental health. The initial impression of this book was that it would be a fast paced thriller with a stunning conclusion. However, it is more a commentary on unresolved grief, the assumptions that are made based on race and class, and how one event can shatter the lives of so many. It could still be categorized as a mystery. I found the multiple points of view valuable in understanding the characters and events. Even though, at times, Saint X did not move quickly, it was still a compelling and interesting read.