Mori was on a fishing trip when he accidentally caught a young mer in the net. After the incident, the mer became extremely attached to him, and for the sake of the mer, Mori decided to keep him. He got him into the popular program for domesticating mers, and within five months, the mer - Osamu - was officially his son. He raised him along his other children with his husband, and despite its ups and downs, Mori couldn't be happier with his decision to keep the child.

Now, eleven years later, Osamu is fifteen years old and living happily among humans with Mori and his family. Aside from the expected ups and downs, everything was going smoothly until this current year of highschool for Osamu. See... Osamu hasn't told any of his family this, but he's been getting bullied. Well, that secret it out starting today.

Mori got called to the school building to pick Osamu off - the mer having been suspended for really hurting another kid in a fight today. Osamu got hurt too, having a black eye, swollen lip, and a worrying red hand mark around his neck - but this kid nearly got hospitalized. He was going to give Osamu an earful as he was getting back in the car to drive Osamu home... that is until Chuuya - a boy that lives across from Mori's family, has known Osamu since kindergarten, and is currently dating Osamu - knocks on Mori's car window to talk.

Apparently, the boy Osamu beat up had been bullying Osamu everyday the whole school year. Osamu had done a good job at ignoring the boy, silently taking whatever he dished out until today, when he insulted Chuuya. Something apparently snapped in Osamu, because the next thing Chuuya knew, the two were fighting and Chuuya was pulling Osamu away before he could curb-stomp the bully.

...His son was getting bullied...? For a whole year?? Why was he just hearing about this now!? Thanking Chuuya, he gets back in the car and turns to face his bruised and bloodied son, looking sympathetic but stern. "Osamu. Is there something you would like to tell me?"