Aspiring screenwriter Gu Yunsu quits her job to chase her dream, expecting to rely on her mother for support. However, she is shocked when her nearly 50-year-old mother remarries and becomes pregnant. Now unexpectedly a caregiver, Gu Yunsu navigates life with her strong-willed mother, unfamiliar stepfather, and soon-to-arrive half-brother, leading to a series of humorous and heartwarming family moments.