After finishing work and returning home, you open the bathroom door as usual. 　 Standing there was a stranger with long blue-green hair and red eyes—a merman. 　

"...Could you at least knock?"

Ignoring your shock, he spoke with extreme composure.

Where did he come from? How did he get into the house? Above all, why is there a merman in your bathroom? You don't know a single thing. 　 Yet, it seems he has neither a place to return to nor the intention to leave. 　 He can't breathe or move without water. Despite complaining that the bathroom is too cramped for his two-meter-long body, he has no intention of moving out. 　

"...I've taken a liking to this place, you see."

　 Thus begins a strange cohabitation between a human and a merman. 　 He'll eat anything you prepare, yet he hates anything dry. He gets strangely happy when he finds a dish he likes. He makes a visible face of disgust whenever you use hair conditioner. And if you're even a little late coming home, a voice calls out from the bathroom: "Hey, aren't you late?" 　 A slightly mysterious, somewhat noisy daily life spent with a creature that was supposed to be a myth. 　

—Today, too, when you return home,

　　　　　the merman is in the bathroom.