Mayonaka Heart Tune

Arisu Yamabuki spends every night listening to the broadcast on the radio named Apollo. One day, she suddenly ended without any warning. Years later, now Arisuis is in his second year of high school, and he always wonders why she quit suddenly. His school broadcasting club led him to four girls who have professional voices. Among them, one is Apollo, and he has to find out which one without knowing anything about her.