Nino Arisugawa, a girl who loves to sing, experiences her first heart-wrenching goodbye when her beloved childhood friend, Momo, moves away. And after Nino befriends Yuzu, a music composer, she experiences another sad parting! Luckily, Nino reunites with Momo and Yuzu in high school, but things haven't played out the way anyone expected...

Yuzu and Nino have been tasked with writing the debut song for a popular fashion-model duo. They manage to complete their first collaboration...but to what end? Meanwhile, Tsukika goes in search of Momo, but will she be able to find him when all she has is a questionable lead?