The story is about a young guy who’s graduating from high school.
Before his school life ends, he wants to confess to his crush. Her name is Rei and she quickly turns him down, crushing his dreams in public.
The embarassment turns to motivation as he continues spending the following years in solitude.
During that period, he turned his ordinary smart phone into a time travelling device. His goal was to undo his confession mistake but only ends up sending himself back all the way to the 90s, where he meets a different kind of girl.
One that might end up being his true love.