Seduced by the Three

While secretly practicing piano in an empty music room, Mikoto Moriwaki is suddenly kissed by a mysterious, handsome stranger. Flustered, she flees... only to encounter Kanade Sakuranomiya, the former pianist she's long admired. Kanade kindly offers her a place to stay and formal piano lessons, but her unexpected kissing partner, Keito - also a brilliant pianist and Kanade's brother - strongly objects...!

(Source: MangaPlaza)