Virgins are impregnated with a state-approved but probably unrivaled smartphone. As part of global measures to combat the extremely low birth rate, the government has officially decided to distribute "event app smartphones" to men who can get pregnant, which is being promoted experimentally. With this, Nagata, a bored virgin student, finally gets his long-awaited month-long event privilege. The first person to pair up with him is Mitsuki Nagisa, a beautiful girl who just transferred to another school. She has a shadow for some reason, and it's true that she has a reason. Nagata, who doesn't know about such things, believes that an event will happen as a matter of course, so he approaches her and impregnates her in the name of an event, but... At that time, he had no idea that the encounter between him and her would be the catalyst that opens up a major incident later on...