Qingren (Lee Yoo-young)'s mother became a vegetable ten years ago. She was exhausted physically and mentally from taking care of her mother alone for a long time. The nursing robot codenamed "Guardian" (Lee Yoo-young) not only helped Qingren take care of her mother, but also became a good helper to take care of herself. However, the robot, which seemed to only listen to human commands, had its own troubles. It believed that "only one person can live if one dies"... "Guardian" was a part of the science fiction series "SF8". After it was broadcast, it received unprecedented attention, so it was decided to be officially released in theaters.