Tune In to the Midnight Heart

At the end of a difficult day, the haughty but purehearted rich kid Arisu found his only solace in the voice of another girl his age, who hosted a livestream under the pseudonym "Apollo." Then, one day, the broadcasts stopped. Arisu has dedicated the years to finding Apollo's true identity, and he's narrowed it down to one particular high school. He transfers in as a student and figures it'll be a cinch--but then discovers it could be any of the girls in the broadcasting club, and the real Apollo isn't talking for reasons of her own. These four girls have no use for Arisu's personality, but they each harbor dreams of using their voices to build a career, and they sure could use his money. (from manga)

Synopsis from Anime News Network