The super‑strong three‑year‑old girl Mopsy arrives at Mercer Estate for a companion challenge to win family‑support bonus. She breaks into the isolated young master Nico’s world and helps him step out of the mental shadow caused by a car crash. The two bicker at first and gradually become close friends. However, they get caught up in family‑trust power struggles and face numerous plots and crises. Faced with dilemmas between affection and interests, the two children protect each other, pursuing their friendship and hope with courage and sincerity.