A special included in the Eiga Yes! Precure 5 GoGo! Okashi no Kuni no Happy Birthday movie.

Yuusuke was just a normal kid going to high school. Then one day, the cute and behaloed Noelle fell, quite literally, into his life, naked as a baby and every bit as innocent. Before he can even fathom what's just happened, Yuusuke is inducted into a rather odd family of otherworldly beings. Papa is a Frankenstein monster with a taste for calisthenics. Mama is a gorgeous lady with a penchant for "round objects" -- really! The eldest sister, Sara, is literally invisible; the brother, Gabriel, is a teenage vampire with an attitude problem; and the youngest sister, Ruka, loves inventing things. There's a disapproving Grandma, who's a witch to the nth degree, and her vulture familiar. All Yuusuke wanted was for the beautiful Natsumi to even notice his attention, but now he has an angel-in-training to follow him wherever he goes. And Noelle, too, has a guide on her path to being an angel, the mysterious Michael.

Kai, who has powers different from the rest, together with his sickly sister Hikaru was protected by an organization called ASHURUM. Scouted by Eiji, Kai was delegated to the ASHURUM special force AESES and undergo intensive training. Whenever he was free, Kai visited Hikaru at the hospital belongs to the organization, but Hikaru's condition never improved. So, one year later, with amazing growth from the intensive training, Kai decides to escape from the organization. (Source: ANN)

Taking place after the events of the fourth film, the series centers on 11 yr old Keisuke Amano, Natsume's younger brother (both of whom are the children of Keita Amano and Fumika Kodama of the original Youkai Watch anime) who doesn't believe in any supernatural phenomenon around him. But as he notices his sister is frequently comes back home late, he decided to stalk her, only to find out she is doing her duties exorcising evil Youkai alongside her friends Touma and Akinori, and running a Yo-Kai detective agency. With their secret revealed to him, Natsume decided to let him tag along in her activities as they investigate Youkai crimes and take on evil Youkai to maintain peace all over the city. (Source: Wiki)