Kim Min Kyu is a wealthy and brilliant man who lives alone because any physical contact with people triggers a dangerous allergic reaction. His isolated routine changes when he becomes interested in Aji 3, an advanced android created by a robotics team led by Hong Baek Gyun.
When the real robot breaks right before a crucial test, Baek Gyun asks his ex girlfriend, Jo Ji Ah, to pretend to be Aji 3. She agrees out of financial desperation and steps into Min Kyu’s home disguised as the android modeled after her.
As Min Kyu grows attached to the “robot,” Ji Ah struggles to maintain the lie while dealing with her own feelings. Their unusual arrangement forces both of them to confront loneliness, trust, and the risk of a connection that should not exist.
A side character has a tiny love-triangle-like subplot, but it does not affect the main leads and is irrelevant to the core romance.