Will Matthews is lousy at all sports, but even he knows how to ride a bike. He just never dreamed that it could be such a rush! Soon after he joins a mountain biking club, he's hurtling down hills, pedaling over mud-churned trails, and leaping over rocks and gullies. But is he moving so fast that he's forgotten the friend he left behind? And are all his new friends as "cool" as they seem?