Tsuki no Kanata de Aimashou

Summer, 25 years old―I became a salaryman before I’d realized. Looking up to the sky, I remembered the dreamy days. Reminiscently, I turned on the smartphone I used during my high school days. I opened the messaging app and sent myself a message.
“You will regret it”
A message to my past self. A message that cannot be delivered. But — the phone responded.
“What is this, all of the sudden?”
This is — a message from myself — from the past.