Book five in Angela Hunt's series for children ages 9-12: In the gathering darkness, Nicki and Christine swam quietly toward the Mary Celeste II. The water was as black as ink around them, and Nicki tried not to think of the living things that might be passing by her in the warm water.They reached the stern of the boat where the overhead light on deck threw shadows in the water. Nicki lifted her face mask. "Are you going to climb up, or should I?"

Christine's mouth fell open and her eyes bugged. "Behind you," she squealed. "Look!" Nicki whirled around. Behind her something was rising out of the water-something big and dark and sinister, with arms like a giant sea serpent!Nicki Holland expected fun and sun in the summer before her eighth grade year-not mysterious strangers and counterfeit cash! Nicki, Meredith, Kim, Christine, and Laura are warned to leave the mystery alone. But when Nicki is threatened, she has to solve the mystery to save her own life!