See You On the Other Side of the Moon Switch -

If I could meet you again If you could connect the future and the past with a smartphone, what regrets would you redo? The summer of their second year. These girls were more mercurial, more mysterious, and more beautiful than anyone else. My first love. Sweet and bitter memories. With regrets, the summer days passed. The summer of my 25th year. Before I knew it, I had become a salaryman. Looking up at the sky, I suddenly remembered those dreamlike days. As if reminiscing, I turn on the smartphone I used in my student days, launch the messaging app, and try sending myself a message. "You'll regret this." A thought directed at his former self that was never going to reach him. But then his smartphone vibrated. "What's this all of a sudden?" It was a message from his past self...