According to rumor, "The Cats" reign over the streets of Treasure Town, privy to all its happenings, and no trouble can arise without their approval. In truth, this is the moniker of two fearless orphans, Black and White. Their sovereignty over the streets is endangered when the Yakuza descends upon the city, enforcing alterations. With nobody to rely on save for each other, the adventurous Black and lighthearted White must restore Treasure Town to its former glory. However, they soon discover that returning to status quo may not be possible, and their bond is put to the test.