I originally went in reading this webcomic first and thinking it would be slightly different than the book version, but they were both the same (except for some differences throughout and at the end of the book). 

It was soooooo good and actually very heartwarming. The MCs were both on the hunt for letters left by another classmate and it was an effort to bring them together and learn about the classmate that left them. The classmate has a secret that will surprise them both and it was just very sweet seeing how healing this whole process was for the two of them 💕