They're just regular idols who can't label what their relationship is... but they both knew its deeper than just "friends". 

Chaeyoung decided to take a stroll down the familiar path of the street at her home town trying to reminisce about the past. Despite how painful it had been, there were no regrets.  However, the past caught up to her as if fate was playing its part to rekindle an old flame after being separated for 45 years.