Frog and his friends live happily together on the river. At least they do until Beaver comes along. Beaver is determined to build the biggest and best dam anyone has ever seen, and he doesn't stop to think about what that will mean for everyone else's homes. Frog tries to tell Beaver that his dam is getting too big, but Beaver just won't listen. Before long, Beaver's dam is so huge that it stops all the water in the river, and Frog and his friends must move upstream. But diverted water also needs somewhere to go, and soon Beaver will learn that only one force is stronger than a mighty river---friendship.