After School Nightmare

After School Nightmare (Japanese: 放課後保健室 Hepburn: Hōkago Hokenshitsu, literally "After School Infirmary") is a shōjo manga series written and illustrated by Setona Mizushiro. It was serialized from 2004 to 2007 in the manga magazine Princess and collected in ten tankōbon volumes. It is licensed in North America by Go! Comi, with all volumes adapted by Mallory Reaves and edited by Brynne Chandler. The story is about Mashiro Ichijo, an intersex high-school student who is forced by a teacher to work out their gender identity in a collective dream, and Mashiro's romantic relationships with two classmates, one female and one male.

Story
Mashiro Ichijo is a girls' idol, handsome and kind, but he has been hiding a secret all his life; he's not truly male, nor entirely female. He has the upper body of a male but the lower body of a female. When a mysterious school nurse introduces him to a new class, he finds that in order to graduate he has to go to a world of dreams to find a mysterious key, competing with other classmates to find it. Once this key is found, the student graduates and all other members of the school forget the finder's existence. As he struggles with his gender identity, he tries to decide whether he wants to live as a male and go out with one of the prettiest girls in school or as a female and be with the cute male slacker, both of whom are madly in love with Ichijo.

The final chapter reveals that the whole story is an allegory for an outer story that was hinted at on the first page and then hinted at repeatedly during the course of the story: The school is connected to a ward of pregnant women and when a student graduates, they are born in the real world. Mashiro is reborn as a girl, whose twin brother died right before birth. In the epilogue, the real-world analogs for Fujishima, Mizuhashi, and Ebizawa are shown, with the real-world Mashiro and Mizuhashi meeting by coincidence when catching the same train to school.