Calvin Wheeler, a cunning 13-year-old with a seemingly perfect life, is missing just one thing: an original edition for his cherished comic book collection. One day, while skateboarding, he is pursued by a valuable show dog, whose owner unintentionally persuades him to adopt and train a dog himself. The only option available is Tyko, a rough-around-the-edges Labrador/St. Bernard mix from a nearby animal shelter, who turns out to be quite a handful.