Ever since her father used up the last of the family fortune and skipped town, Kanae Otowa has lived in her family's ancestral mansion, Otowakan. With no way to pay off her father's debts, Otowakan is being foreclosed and Kanae must oust the remaining residents—her friend Sousuke Kagura, and two strange people who claim to be her father's acquaintances, Wolfgang Amadeus Mozart and Ludwig van Beethoven. After somehow being resurrected, Mozart and Beethoven have started going by "Motes" and "Beethes" respectively, and begun to indulge in a variety of idiotic, non-musical pursuits.

While stubbornly refusing to leave Otowakan, Beethes unlocks the hidden power of Musik, saving Otowakan from demolition and delaying his eviction. With this discovery, other Musik users are drawn to Otowakan, including Frédéric Chopin, Franz Liszt, and Franz Schubert. However, not all Musik users have innocent desires. Across the city, the enigmatic Johann Sebastian Bach sits atop a tall building, plotting how to use his Musik.