Last First Kiss

Keiri Akashi, A 17 years old full blooded Japanese who grew up in United States has been happy all his life, being able to spend his everyday life with his loved one, Kennoh Rae Lim. Kennoh has a mixture of Chinese and Filipino blood in him, he's 18 and is staying in the United States where him and Keiri are the best of friends. He has a sister named Mary Rae, and she's 16 years old, Mary on the other side, has her own world where her life is full of sadness and no one can pull her from drowning, would someone out there can do that? Keiri had everything he could wish for, the love, the joy, the future plans they both talked about, but the major turn of event made Keiri believe that at the end of the day, all those borrowed happiness would return to its rightful owners, just like Kennoh did. So what if Keiri believed that parallel universe exists? Would his past self receive warnings about the turning of events that will happen? Can he save Kennoh? Can he save their future?