MC and FL have been married for 7 years, but the wife's feelings have cooled down and she's even seriously contemplating divorce... It seems she had an affair with a coworker, too, though it's not certain how far they went. Then she gets in an accident and loses her memories of the past 13 years, returning to her 16-year-old self. They were already dating back then, so her feelings for the MC more or less return and this is an opportunity to start again. However, it's quite a mess, the coworker is still around and hasn't given up on the FL.