It's the Kaimei School Festival, and Bossun's class is doing a maid cafe. Everybody's parents show up, and Bossun is approached by a man who claims to be the doctor who delivered him. He has finally decided to tell Bossun the truth of what happened that day, which he has kept secret for 17 years...
In other words, my parents were 
not my real mother and father.
Por eso me di cuenta que ellos 
no eran mis padres biológicos.
Es decir, que mis padres
 no eran mis padres biológicos.
Ou seja, meus pais não são
 meus pais de verdade.