Kim Min Gyu gets an allergic reaction when in contact with humans, but he says he isn't lonely.

Min Gyu believes Ji A is a robot and agrees to train her for a month, making Ji A face many obstacles.

Min Gyu decides to keep Ji A. Meanwhile, Ji A discovers Min Gyu is the head of KM Financial.

Min Gyu orders Aji 3 for trial. But that night, the research team accidentally spills beer on it.

Baek Gyeon wonders if it's okay for Ji A to stay with Min Gyu and realizes he still likes her.

Ji A goes to Min Gyu's house. She makes her first mistake, but she must keep pretending she's a robot.

Ji A discovers Min Gyu is her brother's boss. Meanwhile, Yoo Cheol hears about Santa Maria and Aji 3.

The cause of Min Gyu's allergy is told. Also, Ji A saves Min Gyu's life when he gets an allergic reaction.

Baek Gyeon punches Min Gyu, brings Ji A home, and tells her she doesn't need to see Min Gyu anymore.

Ji A kisses Min Gyu first, which makes him feel confused and makes him keep a distance from her.

When Baek Gyeon sees Min Gyu ordering Aji 3 to do household chores, he volunteers to do them himself.

Baek Gyeon realizes why Ji A broke up with him. Meanwhile, Yoo Cheol shows up at the start-up competition.

Baek Gyeon is shocked when Min Gyu says he likes Aji 3. Meanwhile, Dr. Oh tells Ji A about his allergy.

When it is time for Ji A to leave, Min Gyu shows Baek Gyeon his allergic reaction to keep Ji A by his side.

Min Gyu learns how to kiss and tries to kiss Ri El on a date. Baek Gyeon follows them in secret.

When Martin becomes impatient, Do Won promises that Aji 3 will be ready soon. Min Gyu tries to protect Aji 3.

Yoo Cheol learns about the cause of Min Gyu's allergy and decides what to do about the board meeting.

Min Gyu becomes hopeful of curing his allergy. But Baek Gyeon is mad that Min Gyu and Ji A are getting closer.

Min Gyu sees Ji A on the train and follows her. Min Gyu almost finds out the truth about Ji A and Aji 3.

Min Gyu tries to stop Do Won and bring Aji 3 back, but Aji 3 is nowhere to be found, making Martin furious.

Ji A pursues her own dreams, while Min Gyu and Yoo Cheol become good partners in leading KM Financial.

Baek Gyeon says Aji 3 will be ready in three days. Min Gyu goes on a date with Ri El and meets her dad.

Min Gyu calls Ji A for a delivery service, but she rejects it. Meanwhile, Ji A sees Min Gyu with Ri El.

Min Gyu tries to stop Ji A from going away, but Ji A tells him that she isn't Aji 3 but only a model for it.

Locked up in a storage room, Min Gyu tells Ji A about his story. She feels sad but decides to leave him.