Lawyer Kim Dongwoo worked hard for all his life, yet he has achieved neither a family nor a career that brings true satisfaction. The lawsuits that fail to progress properly and a broken family have become overwhelming sources of stress for him. Perhaps because of this, Dongwoo suddenly becomes a primitive boy living 25,000 years ago. But it feels far too vivid and real to dismiss as just a dream. The life of primitive boy Dongwoo unfolds with his primitive family and the great wilderness of nature. How different is that life from the present one? Or perhaps, how similar?