Ryoto Arima is an alpha college student. One morning he woke up to find a beautiful omega sleeping in the same bed with him. I don't remember, but we had a one-night stand...!?

Arima can't stop thinking about him and finds a diary on his phone that he doesn't recognize. In the diary, a picture of the omega this morning, the name “Saku Yu” and the words “Maybe I keep forgetting Saku-san” are written...

A single-minded and straightforward college student x A novelist who disappears from her lover's memory every new moon A story of destiny between two people who cross paths again and again.