The cousins are excited for their first campout on Lost Island with their friends Vimila and Anupam [from #8: The Case of the Spying Drone]. When they hear distressing cries of an animal and from their Lookout Tower see what appears to be a baby bear on the shore of Grizzly Paw Wilderness, limping and shivering, they want to save it. They fear its ferocious mother however, especially after discovering that a bear has ravaged their fort and food. Plans for rescue are thwarted by a storm, making it dangerous to row across the inlet. Worse though, their boat has come untied and is drifting out onto the lake: They're stranded! Growing hungrier by the hour the five kids must decide how to safely leave the island before their parents begin to worry.