In a whimsical tale of romance, Kouno Jun, a spirited individual, embraces life wholeheartedly. His heart captivated by Hasebe Rino, the enchanting beauty of his kindergarten class, he bravely declares his affections. Surprisingly, Hasebe reciprocates, yet in a baffling twist, she instantly vanishes after her response, leaving Kouno perplexed. Struggling to unravel this mystery, Kouno discovers that all recollection of Hasebe has vanished from everyone's memory except his own. As Kouno navigates through the challenges of high school with a sense of yearning and confusion, a new student arrives – Hasebe, but with an unexpected twist to her identity, unlike the Hasebe he once knew.