KPOP - Astro - Finding Fate

In their world, everyone has a small imprinted timer on their wrist they are born with. The timer counts down to the hour they meet their soul mate. When they do meet, both person's imprints change to become the date that they met and last forever as a sign of promise and eternal bond. But suddenly Dongmin's changes over night to a much sooner date - 3 days away...