My Perfect Stranger: Season 1, Episode 2

1 - 2: The Reason We Can't Return

Despite her confusion about the current situation, Yoon Young recognizes a small possibility of altering the future after a chance encounter with 19-year-old Soon Ae, prompting her to follow her closely. Soon afterwards, Yoon Young learns about the mistreatment that Soon Ae is facing from the other kids and also notices that some of the children resemble those she knew from the future.