Boku wa Konya, Imouto to

"I've never thought of you as my sister." Then, a brother's lips brushed against those of his sister...Haruichi, who is two years older than his sister Natsumi, is the kindest, the coolest, and the bestest older brother one could ever have. It's easy to be jealous of how well they get along, and yet... the balance between the two begins to crumble...