Kouki and Shiori are high-school students who fall in love for the first time in the month of April among the dancing sakura; but their experience with these new feelings is as tentative as the slightest wind of the changing seasons.
Even so, never a day goes by that isn't stirred by their first love. The scenery they view from inside the Ferris wheel, walking on the streets together through the rain?in this fashion, the red thread that ties these two together grows stronger as time passes. This is the story of how they live their lives through the first six months of their relationship.

Based on DECO*27's popular Vocaloid song "Mozaik Role":

Megumi Nakashiro never believed in doppelgangers or any of that occult stuff. Sure, she was a member of the occult club, but that was only because her boyfriend Kubohara was in it. However, her view starts changing when her boyfriend suddenly disappears and a girl named Megumi Kokusenya joins her class..