A virgin is impregnated with a state-approved smartphone, but it should be unrivaled. As part of the global measures against the ultra-low birthrate, the government has officially decided to distribute "smartphones with event apps" to men who can be impregnated, which was being experimentally promoted. With this, Nagata, a dull virgin student who finally got the long-awaited one-month event privilege. The first time he matches him is Mitsuki Nagisa, a beautiful girl who has just recently transferred to another school. Somehow she has a shadow, and it's true that she has a reason. Nagata, who doesn't know about such things, believes that an event will take place 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 way of knowing that meeting her would be the catalyst for the beginning of a major incident later on...