The Two Sisters aka In Cold Blood: 1x31

Episode 31

Min Tae comes to see Hye Won at her place and runs into Do Eun. When Min Tae realizes that Do Eun is his long-lost daughter, Hye Ji, Do Eun threatens him to stay quiet. Meanwhile, Hye Won asks Do Eun about what happened between Min Tae and her earlier in the day, and Do Eun shoves her as hard as she can so that she falls down.