Kim Min Gyu has wealth and success, but lives an isolated life due to his allergy of people. He then meets and falls in love with a girl who is pretending to be a robot for her ex-boyfriend, a genius robots professor.
Kim Min Gyu is the largest shareholder of a financial company. He suffers from a "human allergy", preventing him from normal interactions with other people. He becomes interested in a robotic project named Aji 3 created by the Santa Maria robotic team. The team is headed by Hong Baek Gyeon, inventor of Aji 3 and world-renowned robotics professor. He modeled Aji 3 after his ex-girlfriend, Jo Ji A, a struggling inventor that also works as a personal shopper to make ends meet. Just when Min Gyu wants to test the robot, an accident causes the malfunction of the robot's battery. Baek Gyeon begs Ji A to take the place of Aji 3 and pretend to be the robot so they can get funding from Min Gyu. But Aji 3 becomes the closest thing that the lonely Min Gyu has to real contact with another person.