Top intelligence agent Cheng Shu took on a mission to "steal a decryption key", but was forced to become a babysitter for a five-year-old cute kid first. Babysitting during the day and infiltrating at night, yet the little one was harder to fool than a security system! When the wealthy conspiracy behind the mission surfaces, he must make a choice between the astronomical commission and the mother and daughter he desperately protects. Top intelligence agent Cheng Shu disguised himself as a babysitter just to steal the top-secret key hidden in the children's projector. But the five-year-old cute kid pierced through his lies time and time again. Until the behind-the-scenes employer surfaced, he discovered that what was truly meant to be destroyed was never the key, but the truth.