Hiroshi found a broken cellphone on the street and went to a shop to get it fixed. When it got delivered to his home, he got a life-sized girl instead but it is still a cellphone. Hiroshi only wants a normal cellphone that he can brag to his classmates but he can't return this one because of the expensive return fee written in the purchase contract. This is how Hiroshi discovers the advantages and disadvantages in life of owning a cellphone-girl, which he named Eko.

(Source: MU)