Gyeong Ah works as a caregiver and lives alone. The only one she can rely on is her daughter, Yeon Soo, but it's hard to see her after she moved out on her own. Meanwhile, Yeon Soo, who is suffering from her ex-boyfriend, Sang Hyun, argues with him again and visits her mother’s house. After Yeon Soo left, Gyeong Ah receives a shocking message from a stranger.