Mason Williams dominates short races in the pool, but his endurance is not up to speed. When one of his teammates taunts him that he might never "swim with the big fish," Mason vows to train harder. Luckily, his best friend Alex has a great idea . . . to swim in a nearby lake to build up his strength. Alex paddles his kayak beside Mason as he swims in the lake each day after school, and soon Mason starts seeing results. But when the two friends have an argument, Mason might take his training too far. Will Mason be able to swim the distance?