My name is Akagi Natsuki (かき), which is not a persimmon, nor an oyster, but Natsuki.
In fact, I know that whether my classmates or my cousins are calling me oyster, they all call me oyster.
My brother's name is very nice, Akagi Harunobu.
But when it comes to me, it's called oyster.
I hate oysters.
He hates his cousin Yukimura Seiichi who likes to eat oysters.
Especially when he tried to pry open my shell.
——————————————————————————————
The male protagonist is a gloomy, introverted and unsociable man who is paralyzed on the surface but complains on the inside.
The male protagonist's cousin is a goddess with a cheerful appearance, but a dark, cheerful and gentle heart.
Well, in general it's a story about a cousin trying to pull his cousin out of his own inner world.