A teen and his stepdad fight off a monster in this novel for reluctant readers.Seventeen-year-old Kai Lee is not happy about going into the wilderness with his new stepfather, scientist Rick Ortiz. He doesn't like Rick and is definitely not interested in spending two weeks helping him with his research despite his mom's hope that the two of them will bond. Kai hates the floating research station and finds the dark water oppressive. Even worse, his phone has no reception. The only bright spot is that he got to take his dog, Alfie, along. Rick is investigating why the last underwater robot mapping some underwater caves vanished; he's going to send another one into the water. However, it's difficult for Rick to stay focused when Kai takes off running into the woods with Alfie and comes back telling a skeptical Rick that he was chased by a monster. When the monster returns, Rick has quite a shock, and he and Kai work on a plan to try to stop the monster from wreaking havoc. Kai has been justifiably angry since his father left his family, and some readers may identify with his anger management struggles and resentment toward Rick; others may find caring, well-intentioned Rick more sympathetic. Although the premise is exciting and the fast pace will keep pages turning, the emotional resolution happens too quickly to feel earned. Characters are minimally described; their names may cue ethnic diversity.A mixed bag. (Fantasy thriller. 12-18)