Originally, the zodiac earned their places in a foot race. But the rules have since changed; every one thousand years, a new set of zodiac are to be chosen in a battle based on happiness! This is the free-for-all known as the Zodiac Royale, in which each one of the animal participants will be bound by fate to a human "master" on earth. Only bringing their master happiness will allow them to move up in the rankings.
When Ichika Kotobuki, a closet fan of tokusatsu—shows with superheroes and extravagant special effects—tries to help a wounded dog, she is drawn into the Zodiac Royale as the master of the dog Komamaru. Though reluctant at first to participate, Ichika agrees on the condition of prosperity for an entire year if they win. If Komamaru wants to make Ichika happy and secure his place in the zodiac, he is going to have to be just like the tokusatsu heroes—flashy but noble nonetheless.