Yet another manga that I collected in full but have only read the first couple of volumes of...
The story starts off implausibly, to say the least. Mizuki, a high-school girl, cuts her hair short and binds her chest, and transfers to the all-boys' school that her high jumping idol Sano attends. Not one chapter into the story, three of the other characters know her secret, including the school's gay doctor (yes, a gay man has an intuitive grasp of her gender, sigh) and the campus's mascot dog. And Sano, who ends up being her roommate!
The premise, as unbelievable as it is, sets up a situation where Mizuki can readily become friends with a bunch of guys without it seeming like a reverse harem story. One of them, Nakatsu, is developing a crush on her and--thinking she's a boy--agonizing about what that might mean about his sexual preferences, but it's all very silly and harmless.
Sano is the cool and aloof type so we won't know for sure what he's thinking 'til the end, probably. He indulges Mizuki to an absurd degree for somebody who barely knows her, protects her from her own mistakes, and gives her the privacy she needs as a secret girl roommate. And he is not even the slightest bit creepy or dangerous.
Cute fluff, fun and pleasant to read.