Detective Pennington Wise and his assistant Zizi have yet another 'locked room' mystery to solve. The Varian family have rented a house for the summer, built on a cliff and surrounded by water on three sides, there is only one way in, and out. As they are heading out for a picnic, their daughter Betty returns to the house to get her camera. When she does not come back out, her father goes to find her and never returns. Carolyn Wells tackles the locked room mystery genre with a robust plot, clever writing and a flair perfect for fans of Agatha Christie.