This movie mainly revolves around Na Bo-ra who is an adult now, she was forced to peep into her teenage life when she received an invitation from an anonymous person.
Yes, The film begins with an adult busy Na Bo-ra in 2019. Then it is shown that 17yo Na Bo-ra and her bestfriend Kim Yeon-du discussing about yeon-du's surgery and crush.
This whole film is set in the end of 20th century i.e 1999. Na Bo-ra who founds out the crush of yeon-du & finally follows him where she falls in love with another school boy. 
Then it shows yeon-du comes back after successful surgery and both realizes that they fell in love with the same person but was misunderstood due to name badge. Later, it shows both yeon-du and bo-ra ready to giveup their love for friendship.
Bo-ra & the boy stays in contact eventhough it's long distance. The one who promised to comeback right after school & never returns back. Bo-ra then realizes truth behind everything that happened in the 21st century.
To be honest, I thought this film will be a rom-com comedy drama with breakup and finally patching up with each other. I always ignored this film whenever I get pop ups while I open the app. But it turned out be wholesome, it made me cry and and and... no words to explain how they directed the whole film it was soo good.
Loved the way of friendship that bo-ra and yeon-du had, Woon-ho is an epitome of green flag even hyun-jin too was a green flag. Some people are like that they co-operate and are kind full. Literally loved the storyline & even climax but it is like happy & sad at the same time type of climax which is teary, heartwarming and good for your soul. And I loved the way people lived in 20th century before advancement of internet, I don't remember that century but atleast I'm super glad that I was born on that century. Most of them will love this film.❤️
Na bo-ra realized that someone had happiest moments while with her in his short life. Later, she watches her teenage life which was recorded by woon-ho.
Note: I hope you guys would watch this film which is streaming on Netflix btw if there is any grammatical mistakes or anything is incorrect, comment and correct me. As we known humans are imperfect.
Let me know if you guys have already watched this film & how it was for you.
