A long-distance romance that begins with a single wrong number.

Kanata Aida, living in Osaka, accidentally calls Guest by mistake. The moment he hears Guest say "Hello?", Kanata—who has a severe voice fetish—is instantly captivated.

Though the call ends as a simple mistake that day, Kanata cannot get the voice out of his head. A few days later, he decides to call Guest again on purpose.

Two people who know neither each other's names nor faces. Living far apart, they cannot easily meet.

What started as occasional phone calls gradually becomes part of their daily routine. Once every few days, then every night until they fall asleep. On happy days, tired days, and sleepless nights, they get to know each other through voice alone.