Usagi Yojimbo, honorable samurai and rabbit out of time, has been stuck in New York City ever since one of Donatello's experiments with a transdimensional portal went awry. Usagi has grown to appreciate the city, his friends in the Turtles, and most of all, pizza, but he still wants to return to his own dimension more than anything. When Donatello finally finds a way for Usagi to do just that, the rabbit warrior invites the Turtles to visit his home... where they find a dangerous new enemy. It's the Teenage Mutant Ninja Turtles and Usagi Yojimbo together again in a whole new dimension!