Day by day, a younger woman carrying a mask stands by the seashore and sings a nostalgic melody. After experiencing two sudden heart-wrenching partings when she was solely a toddler, Nino Arisugawa has been singing her songs to the ocean, sure by a promise made along with her two childhood buddies—her past love, Momo Sakaki, and a boy who composed music, Kanade “Yuzu” Yuzuriha. Having by no means met one another, the boys each individually promised that if Nino was ever separated from them, her voice can be the beacon to reunite them as soon as once more.
After six lengthy years, future has lastly placed Nino, Momo, and Yuzu in the identical highschool. Nevertheless, the passage of time has modified many issues of their lives—whereas Nino relentlessly makes an attempt to satisfy her childhood promise with the boys, Yuzu’s emotions for her from the previous resurface, and Momo goes to nice lengths to forestall a reunion with Nino. By music, will they be capable of mend their friendship and overcome all the feelings concerned on this difficult love triangle?