The spectacular succubus, Sakura, has fallen in love with a total social shut-in that only leaves her dorm room for music classes. Don't ask how that happened, she barely knows either!
All Sakura does know is that Hana, the total music nerd, needs to be hers.
No matter what it takes!
Of course that includes some liberally applied devil brainwashing magic and fighting Hana's nightmares filled with music.