To my past self, my past friends and my past girl, 

By the time my son, Jongdae and his friends give you this letter, the future might be changing drastically as I've already told him the rules of time travelling. I told him not to reveal too much of the future as you, my past self and friends might change the major part of the future. However, when you'd read this letter, that meant my son and his crew are already lost in ideas of their mission. You see, my son and his friends had decided to build their own time machine with one mission in mind: Saving Uncle Sehun. Me, Minseok and Luhan were furious the moment they told us their invention as they had already travelled back to the past. Time travelling is dangerous and it will always be. I'm not denying that I was worried every single minute passed without him in this house but his mother, my wife often assure me that he will be fine. He and his friends will complete their mission and will be back safely. I know immediately they will encounter obstacles to finish this mission. Together with this letter, we had provided a few pictures of us together in the future as proves that the boys are from the future. 

Guys, our sons main mission is to safe our friendship. Our brotherhood was broken. It was destroyed even before we graduated. I agreed for them to do this mission while they are on their summer vacation because I want to save our relationship back. I know it is a shame on me to not be there and save it on my own but believe me, it will be better if I'm not there. Their mission, Saving Uncle Sehun as what they called it is to safe Sehun from marrying Eunjung. If you can see, there's a picture of Sehun's and Eunjung's wedding day. If you see it thoroughly, not everyone was there. That was the start of our broken relationship. I was there from the beginning till the end. Our broken relationship resulted in death and hatred. In the pictures of us having vacation together, Baekhyun wasn't there. Chanyeol wasn't there. Lay, Kris, Chen. You guys weren't there. I will not say anything on why you guys aren't there but I will now tell you the true reasons of my boys to be there. 

You see, when Sehun got himself into force marriage, he'd destruct his own future. Sehun in my time look a lot more older than me, Minseok and Luhan. Eunjung was a great woman. She's a nice young woman back in your time now but on her wedding day, she change completely. My house was right next to Sehun's and my son's bedroom is the nearest place to hear them fighting. Ever since Sehu