Late one night, twenty five year old Nana Nanasawa receives a text from her former high school crush, Aya Seto, asking to meet. They have not spoken since Seto's wedding, but Nana enthusiastically agrees. The two pass time as if nothing has changed since their younger days until Seto reveals she is in the middle of a messy divorce. They end up drinking the night away. Waking up hungover the next day, Nana quickly suspects something is wrong. Believing she has somehow traveled ten years into the past, Nana revisits the place where Seto should be on that day. To her surprise, her crush stands there exactly as she remembers.

Nana initially tries not to interfere with history, but is forced to act when Seto is almost hit by a distracted driver. Introducing herself with the pseudonym Mai Sasaki, Nana abruptly resolves to express her feelings for Seto, no matter how assertive she must be. However, she soon encounters an unexpected romantic rival: her own past high school self. The story follows Nana navigating this complicated time slip while using a fake identity, trying to win the heart of her former crush while also competing with the younger version of herself.

The main character is Nana Nanasawa, a 25 year old woman who finds herself transported back in time and must balance her adult perspective with her unresolved feelings. Aya Seto is Nana's former high school crush, now younger as her past self, unaware of the complicated situation unfolding around her. The younger Nana serves as an unexpected rival, creating a strange love triangle involving the same person at different ages.

The manga, written and illustrated by Fuki Hinohara, was serialized in Young Magazine Web from April 2021 to March 2022 and completed with 28 chapters collected in 4 volumes. The story begins in a contemporary Japanese setting where Nana and Seto reunite as adults, but quickly shifts to the past as the time travel premise takes hold. The narrative explores themes of regret, second chances, and expressing feelings that were never confessed the first time. While the initial setup focuses on Nana's attempts to pursue Seto under a false identity, later developments introduce complications arising from Nana needing to conceal her true identity not just from Seto but also from her younger self. The time travel premise adds a layer of tension as Nana must navigate her actions carefully, aware of how they might affect the timeline she remembers.