When the lead dog is injured during the Teen Sled Race at the annual Trappers Festival, the four Mighty Muskrats suspect foul play and must solve this chilling mystery before another so-called accident happens.

Even though he is the runt of the litter from her father's prize sled-racing dog, ten-year-old Rachel plans to train her puppy to become a champion racer and determines to track him down when he mysteriously disappears.