At first glance, Lucky Sonoda appears to be a mediocre middle school boy, but he is actually one of the Otogami septuplets—a group of genius piano-playing siblings. Out of the seven, Lucky is the only one who lacks his siblings' talent, earning the ire of his equally talented pianist father, Gakuon. Publicly, the Otogami siblings are known as sextuplets due to Lucky's ostracization from the family following their parents' divorce. Because of his mother's subsequent hospitalization, Lucky now lives with his abusive aunt who treats him like a housekeeper. Despite the suffering he has endured, Lucky still loves the piano and plays it whenever he visits his mother in the hospital. One day, he is surprised to find his mother awake and off her medication. She laments that she was unable to give birth to Lucky as a genius, which saddens him—he does not blame anyone but himself for being a failure. When he seeks her guidance, his mother encourages Lucky to prove to his father that the talentless can also play the piano. This inspires him to take the entrance exam for the prestigious Shibuya Music High School, where his unique, albeit mediocre, playstyle catches the attention of Hideo Dada—his father's former teacher. After his admission, Lucky finds himself being tutored by Dada alongside a reluctant Ako Furusu—the class representative yearning for vengeance against Gakuon for pushing her pianist mother out of the spotlight. [Written by MAL Rewrite]