Don't Mess with the Ninja Puppy! — Nancy Krulik

When Sparky's magic bone blasts him to Tokyo, Japan, he discovers a whole new world--one with karaoke, "squishy fishy" and sumo wrestlers! His new friend, an Akita named Nanami, guides him around the city, until Sparky loses her in a crowd. But it turns out Nanami isn't just any Akita. She's the queen of the Ninja Dogs--a fierce group who are convinced that Sparky has kidnapped her! To make matters worse, the Ninja Dogs have Sparky's magic bone, and won't return it until he leads them to Nanami. It's up to Sparky to reunite the Ninja Dog family so he can return home to his own!