One day high school student Sora Kashiwagi receives a coffin sent by his adventurer father and inside it is a little mummy that just wants to be friends.

High school student Sora Kashiwagi is accustomed to receiving bizarre presents from his father, who is on an expedition around the world. Unfortunately, these gifts have been nothing but nightmares. As a result, when his father sends him a huge package from Egypt, Sora prepares himself for the worst, only to be greeted by Mii-kun-a cute, pint-sized mummy. While initially wary, Sora soon learns that Mii-kun is harmless, a delicate creature yearning for attention. Throughout their amusing day-to-day lives, the unlikely pair meet other people with unique pets, while also strengthening their bond together. Although keeping a pet is a difficult task, Sora is set on caring for the lovable Mii-kun.—MAL Rewrite

Kashiwagi Sora is living a normal high school student life, when his "adventurer" father sends him a mummy from his travels in Egypt. Sora balks at the letter from his crazy dad ("I found a cool mummy, so I decided to leave it with you, son!") at first, but the mummy that emerges from inside the huge coffin is a mere 12 centimeters tall--small enough to fit in the palm of his hand... Not only that, it's shy, a crybaby, and most of all, heckin' cute. And so, Sora and ends up keeping the mummy, naming his new little buddy "Mii-kun." But living with a mummy might be easier said than done...!.—Crunchyroll