Kamioki-jima is an island close to Japan which was recently formed due to volcanic activity and is home to one of the rarest minerals, enigmatite. Living beings which fuse with enigmatite gain great powers. Such humans are known as "unleashed", while animals and plants are known as "neoplasm" (NP). To research the hidden powers behind enigmatite, the island was designated a special area with a school to train the unleashed, called the "Unleashed Nursery".

Ayumu is a rare male unleashed who has a special ability, ‘engage’, which boosts the powers of his female partner. However, to activate his power, there must be an exchange of bodily fluids. The school president pairs him up with the most powerful student, Kanae, who always maintained her distance from him. One day, the island was attacked by NPs and in order to defeat them, they activated his "engage" ability with a kiss.

[From Hau~ Omochikaeri!]