It's a "Heartsrings" reunion, as Lee Hyun Jin joins Kang Min Hyuk on today's episode! At Tan's boring birthday bash, Bo Na leaves Chan Young's side when she spots a close acquaintance. Chan Young is jealous as he watches his girlfriend "flirting" with the other man. When Bo Na introduces her oppa (Hyun Jin) as her brother, Chan Young is full of chagrin and nervousness. Meanwhile, Hyo Shin, Myung Soo, and Bo Na snicker at his embarrassment.