In a real world where magic, demon lords, and other worlds were believed to be mere fantasy.

Natsuno Naoto discovers a mysterious creature resembling a slime, something that shouldn't exist in this reality.

The slime appeared to be weakened, so after he helped it, it became attached to him and followed him all the way home!

Unable to bring himself to send it away, he reluctantly started keeping it. One morning, several years later, he woke up to find an unfamiliar beautiful girl happily munching away on his food.

As Natsuno Naoto stood bewildered, questioning who on earth she was, the beautiful girl declared,

"The slime form is an energy-saving mode for space-time travel! This form, now that I've eaten and regained my strength, is my true form!" she announced with a triumphant smirk.

Can he ever hope for a peaceful life from this point onward!?