Once childhood friends now almost strangers.

Lee Seunghoon and Jang Sunmi were inseparable from birth after their parents
befriended each other at the hospital's delivery ward where the two were both born on the same day & time. From casual sleepovers to even 
sharing their first kisses to each other, the two were bound to be together. Until one day, a surprise plane ticket was given to Sunmi on her 18th birthday- little did the two know that she wasn't to return after 6 years. 

6 years had passed and Sunmi had now returned back to Korea.
Just how is the reunion going to end up between the two ex-lovers?