Takumi Tsuzuki is a high school student who attends the Umenomori Private Academy, free of charge, alongside Fumino Serizawa, a childhood friend of his whom always says the opposite of what she feels. He spends most of his time at school fending off Chise Umenomori, the granddaughter of the board chairman and a pampered princess, who is constantly roping him into her eccentric hobbies. After school, he goes to work at the Stray Cats confectionery, a cake shop run by his adoptive older sister, Otome Tsuzuki, until it's time to go to bed. This is the average routine in the day and the life of Takumi. Mayoi Neko Overrun follows another seemingly average day in the life of Takumi. With his sister away from the shop, having gone to save someone else in need of help, Fumino takes it upon herself to wake him up so that he won't be late for their usual walk to school together, giving him a glimpse of her blue and white striped panties in the process. What a nice way to start the day. When Otome returns home, she brings with her a girl named Nozomi Kiriya, whose hair and mannerisms resemble that of a large cat. It turns out that she is a runaway that Otome can't help but take in. Takumi's ordinary days are transformed into splendid chaos as he tries to unravel who this mysterious beauty is and what she's running away from...

For the Takakura family, destiny is an ever-spinning wheel, pointing passionately in their direction with equal tides of joy and sorrow before ticking on to the next wishmaker. With their parents gone, twin brothers Kanba and Shouma live alone with their beloved little sister Himari, whose poor health cannot decline any further. On the day Himari is given permission to temporarily leave the hospital, her brothers take her out to the aquarium to celebrate, where the family's supposed fate is brought forth with her sudden collapse. However, when Himari is inexplicably revived by a penguin hat from the aquarium's souvenir shop, the hand of fate continues to tick faithfully forward. With her miraculous recovery, though, comes a cost: there is a new entity within her body, whose condition for keeping her fate at bay sends the boys on a wild goose chase for the mysterious Penguin Drum. In their search, the boys will have to follow the threads of fate leading from their own shocking past and into the lives of other wishmakers vying for the Penguin Drum, all hoping to land upon their chosen destiny.

The Nocturnal Community Relations Division is a team of people who specialize in solving cases involving the ominous occult creatures of the night unseen by ordinary humans. Young and unsuspecting Arata Miyako has been assigned to the Shinjuku Ward Office of the division, where he meets his fellow members Theo Himezuka and Kyouichi Sakaki. On his first night, Arata finds himself on a mission where he discovers to his surprise that not only does every supernatural creature he once thought to be fictional actually exist, but also that he is the only human who can understand their non-human speech. Arata's surprises do not end there, as later that night, he meets a legendary creature called a Tengu that refers to him as the famous Heian-era exorcist, Abe no Seimei. Unfamiliar with the exorcist, Arata pays no mind and continues to work with his team, utilizing his unique ability to assist in the resolution of their cases. Mistaken by many occult creatures as Abe no Seimei and quickly becoming notorious for his special ability during his work, Arata becomes curious of his origins and invests himself more into solving cases regarding occult creatures he encounters once he learns of a certain connection between himself and the exorcist. However, Arata will quickly find that dealing with supernatural creatures is not as simple as he thought, as danger begins to play a fundamental role in his everyday findings and his ability starts to present an unexpected issue.

The villainous Dr. Hell has amassed an army of mechanical beasts in his secret hideaway, the island of Bardos located in the Aegean Sea. He is capable of controlling mechanized beasts with his cane, and instructs them to unleash devastating attacks. However, Dr. Hell doesn't do all the dirty work by himself; he has his loyal henchman Baron Ashura to carry out his devilish plans. There are also those that will see to it that evil does not prevail. Kouji Kabuto is the young and feisty teenager with a score to settle: his goal is avenging the murder of his grandfather by Dr. Hell. And he might just be able to pull it off, as he is the pilot of Mazinger Z, a mighty giant robot made out of an indestructible metal known as Super-Alloy Z. Mazinger Z boasts several powerful special attacks. By channeling Photonic Energy through its eyes, and unleashing the Koushiryoku Beam, it can cause great destruction. But things get really cool when Mazinger Z launches its Rocket Punch attack. Dr. Hell and his minions might have just found their match!