This one goes straight for the pulse point: Hiyori finally gets the apartment she has been dreaming about, and Soushi is already inside it, and then he kisses her before she can even unpack the question. That is the whole engine, and it is a mean, effective one. The show lives inside her head as she cycles through the only two options that matter, he is messing with me versus he means it, and every time she almost lands on an answer he moves the goalposts. "I was planning for us to stay just friends" is the line, and the childhood-friend-turned-predator flip is exactly the flavor of romance that gets called trashy by people who then read all thirty episodes in one sitting. No side plots, no school-festival detours, just proximity doing the damage. If you have ever wanted a show to skip everything except the part where your heart drops, here it is.

Hiyori finally moves into her own apartment after starting high school, ready to live on her own at last. Her plans crumble when she finds Soushi, her childhood friend, already waiting for her there. Without warning, he kisses her. Hiyori can't tell if he's joking or serious, and at fifteen she begins an unexpected life under the same roof as him. Living together transforms everything between them. Soushi's constant presence and bold affection challenge Hiyori's view of him as just a familiar face she never paid much attention to. For the first time she starts to see him as a man, and as he keeps refusing to give up on her, her heart races in ways she doesn't know how to handle.