When the Mario Bros, Peach, RWBY, JNPR, Sun and Neptune go to Yoshi's Island, Bowser once again kidnaps Peach! With the help of Yoshi and Poochy, along with the crazy Reds and Blues, they set off to save Peach from Bowser... but who's this mysterious girl that's with them?

When the Blood Gulch crew makes a teleporter to find the woman who's responsible for making Church and Simmons go crazy, they are sent straight to Remnant! Will they find this woman... or will they be screaming their heads off while not realizing it's Halloween?

Mushroom Kingdom was at the brink of collapse. One man, driven by hatred, had unleashed a terrible darkness on the land. To brave that darkness, Light rose up, and in the final battle that followed, it prevailed. But that light did more than just banish a shadow... And now these lost souls must brave a new land, with nothing but themselves and the guidance of a star.

When the Grimm invades the Mushroom Kingdom and Mario, Luigi and Peach have been kidnapped by Bowser, it is up to Team RWBY to put a stop to this and save the Mushroom Kingdom! But who's this mysterious trio that's working with Bowser?