Times are simpler in the 1980s. Terry, Gary, and Larry love their maple tree, their boat called the London, and the friendly face of the St. Joseph River. Gary finds comfort on the river, where he can use his upper body strength to row, and almost forget about his wooden leg and lost dreams.

But nothing is simple when Mom spots suspicious characters in the empty house next door and suggests it may be time to move away. And nothing is easy when Dad and Mom assign the boys a summer project to learn about the fruit of the Spirit.

Terry, Gary, and Larry set out to investigate the strange characters and prove that their neighborhood is safe. But then, the detective work backfires.

Can the boys escape the tunnel?