Do Min Joon, an alien who landed in Korea 400 years ago, discovers that he has three months left on Earth. And that is when he meets Cheon Song Yi, the biggest Hallyu star in Korea.
When an actress dies from an accident, Song Yi is immediately the target for blame. She seeks refuge in Min Joon's apartment, uncovering secrets that he'd like to keep buried.
Song Yi hides away in Min Joon's apartment after the suspicious death of fellow actress Han Yoo Ra. Prosecutor Yoo Suk begins an investigation to look into whether her death was a suicide or not.
As the threats intensify, Song Yi turns to Min Joon for help. He slowly becomes more human-like by being around her so often, and agrees to be her temporary manager.
Song Yi thinks stress is contributing to her "hallucinations" of Min Joon saving her. The investigation intensifies as witnesses to Jae Kyung and Yoo Ra's relationship begins to disappear.
Song Yi has difficulty dealing with her feelings for Min Joon, who's also trying to distance himself from her and not reveal his true nature to anyone.
Song Yi refuses to hear what Se Mi has to say about her savior from 12 years ago. Min Joon recovers from his injuries but realizes that his heart is now broken.
Hee Kyung won't stop until he finds his sister-in-law and uncovers his brother's dark secrets. Song Yi and Min Joon can't deal with the fact that he'll need to leave in a month.
Min Joon's powers weaken as he stays on Earth longer than he should. Hee Kyung discovers his brother's true self but it will be more difficult than it seems to have him pay for his crimes.
Hee Kyung must find a way to stop Jae Kyung before he himself ends up on his brother's hit list. Song Yi discovers the price Min Joon must pay if he stays with her.