Tides

Tides by Betsy Cornwell, 294 pages

Noah and his sister Lo are spending the summer with their grandmother on the island. Noah has a coveted internship with a marine biologist, which is his chosen field of study when he starts college in the fall. Lo is hoping to get past her issues with body image and bulimia. Both of them get more than they bargained for when they find out that selkies are real and begin meeting them, especially when they find out that someone in the area has taken the skin of one of the selkies and is using it to keep her prisoner. They want to help, but how?