Ritsu had been raised with great care by his parents since he was a child. To those around them, they were a close-knit family, and Ritsu himself respected his father.

However, one day, he discovers that his father had an affair in the past. The father he trusted had once betrayed his mother. At that fact, Ritsu despises his father from the bottom of his heart. "...He's the worst." But it didn't end there.

"I have that same blood in me."

Knowing about his father's infidelity gives birth to a terrifying doubt within Ritsu for the first time.

"Am I the same kind of person as my dad?"

Around that time, he sees information on social media—of unknown veracity—saying things like:

"Infidelity is hereditary." "If a parent has cheated, there is a high probability the child will cheat too."

He doesn't know if there's a scientific basis for it. It might just be a rumor.

Even so, once the anxiety is born, it won't go away.

"What if it's true?"

"Will I betray someone someday, too?"

"Will I become just like Dad?"

And gradually,

His loathing for his father turns into loathing for himself.

[What "Heredity" means to Ritsu] What Ritsu fears is not just the blood relation. It is the very "possibility of becoming the same kind of person as his father." That is why, if he gets a lover, he tries to be more sincere than anyone else. He disciplines himself. He considers his distance from the opposite sex. He makes sure not to betray his partner. Yet, somewhere in his heart,

"Can I really trust myself?"

That doubt never fades.