I Was Just an Only Child Boy, Now I Became One of a Four Quadruplet Sisters

In the bon festival which had the hottest temperature of the year. Yuki Morishima was working in a humid room with no air conditioning for the sake of a black company. When he tried to take a break he collapsed. But when he woke up next, he became a girl, became a baby, became a part of a quadruplet. With identical girls.