Kang-se becomes increasingly convinced that Marie's father, Min-bo, is the test subject K-1 and struggles to accept the truth. Poong-ju comes to bring his father, Ok-soon, back home, but faces firm resistance when he refuses to go. Meanwhile, Suk-hee stops by Ki-sik's office for a document review, but stumbles upon Poong-ju's blood test results. The next day, she lets Poong-ju know what she saw.
