Olivia and her dog Barkley are inseparable. He's her sidekick, her partner in crime-fighting - they're the perfect pair. But then, Barkley dies and Olivia is heartbroken. She dreads falling asleep because waking up without Barkley is just too sad.
Gradually, however, she realizes that Barkley wouldn't want her to be unhappy for the rest of her life. So she thinks of a way that she cannot only get her own happiness back, but also give happiness to another animal, by adopting a new dog from an animal shelter.
And so Spud joins the family. Spud is a terrible sidekick and crime-fighter - she wants to play with the bad guys not catch them! In fact, Spud couldn't be less like Barkley, but Olivia grows to love her very much because she's just as special in her own way.