Su-ji and U-ri

The Truth Slips Out (1x116)

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Jang-soo lets it slip in front of the whole family that he knew U-ri and Hyun-sung were brothers before their parents found out. At The Courtyard House, Jung-soon tries to help Woo-chang so that he and Sun-young can spend some time together outside the house. After they leave the house with Ah-ra, Jung-soon catches an unwelcome guest as he is trying to sneak out.