Twins Jimmy and Billy want to spend their money, and rent a boat from Griff to take a ride on the lake, but mom tries to convince them to save it instead. As Jimmy and Billy leave, Billy spill the beans to doc that they’re still planning to go hiking to the lake.
At Griff’s boat shop, they offer to take a recently repaired boat for a test drive. Griff won’t do it without a parental consent form, so the boys explore a cave as they hike around the lake. Jimmy takes a tumble down a hole. Is he alright? Billy has to race to town to get help.
Back in town, doc shares with Griff Miller that the injuries were only minor. Will the boys be in trouble? Doc discovers news that could make Griff a rich man, and the boys get an unexpected surprise of their own.