The story is told in a different time line.
In 2019 girls fall in love with boys, but find boys with other girls.
In 2020, the girl has a plan to die for love. The plane crashed, but the girl died, the boy didn't.
In 2021, the girl still loves the boy, she came back from hell and wanted to take the boy, but was stopped by grim Reaper.
Try to decipher it and don't miss every detail XD
Thanks for watching, hope you like it.