Secret Siblings

Taesung and Haeun present an outward appearance of brother and sister, having grown up together in the same household since childhood. However, their relationship is a facade. Haeun has been living with Taesung's family for the past 15 years, as her parents chose to reside abroad. This arrangement has fostered a bond between the two, with their familial relationship evolving to be indistinguishable from that of genuine siblings. An incident sets off a chain of events when Taesung learns a prank from his friends, which involves gauging a person's true feelings by observing their reaction when their sides are grabbed. Eager to test the prank, Taesung attempts it on Haeun that night, but his actions are misinterpreted. His hands accidentally land on Haeun's chest, causing her to blush and squirm.