Having put up with the much lower intelligence of humans for 400 years, Min-Joon is preparing to return to his planet when he meets actress Song-Yi.
A distraught and drunken Song-Yi barges into Min-Joon's apartment and ends up falling asleep, and it's revealed that the two have a past connection.
Min-Joon has a premonition about Song-Yi, and when he accompanies her to the hospital for an appendix operation, he tries to subtly warn her.
Min-Joon watches over Song-Yi while she attends a party cruise. Meanwhile, we learn more about Min-Joon's connection with a girl he met long ago.
Reporters are camped out in front of Song-Yi's apartment thinking she killed Yura, so she hides out at Min-Joon's and they get better acquainted.
An intense rivalry has developed between Min-Joon and Hwi-Kyung, both of whom are feeling possessive of Song-Yi. Hwi-Kyung professes his love for her.
Song-Yi tells Hwi-Kyung she doesn't return his feelings. Min-Joon gets more attached to Song-Yi despite himself, and she asks him to be her manager.
Min-Joon saves Song-Yi from yet another accident, but he denies being there when she claims she saw him. Jae-Kyung renews his efforts to kill Song-Yi.
After Min-Joon and Song-Yi kiss, his temperature spikes dangerously high and she tends to him. Jae-Kyung's minions suspect Min-Joon has the USB drive.
Hwi-Kyung and Song-Yi both confront Min-Joon about being Song-Yi's rescuer. Song-Yi's finances are falling apart. Jae-Kyung tries to frame Min-Joon.
Min-Joon reveals his true self to Jae-Kyung before knocking him out. Song-Yi's brother notices her crush on Min-Joon, who keeps coldly rebuffing her.
Song-Yi finds Min-Joon in his apartment bleeding from a serious head wound. Lawyer Jang arrives and warns Song-Yi not to get attached to Min-Joon.
Song-yi finally learns Min-joon's secret. He also reveals that he'd wondered if Song-yi is the reincarnation of Yi-hwa, a girl he met 400 years ago.
Song-yi is in the emergency room after an "accident" engineered by Jae-kyung. Min-joon plans to take the blame for all of Jae-kyung's evil deeds.
Min-joon confronts Jae-kyung about all the lives he's been destroying. Song-yi tells Min-joon to stay away from her, but he does quite the opposite.
Min-joon collapses after kissing Song-yi. Hwi-kyung awakes and pretends he knows nothing of Jae-kyung's schemes. Min-joon tells Song-yi he must leave.
Song-yi questions Min-joon's need to return to his planet. Min-joon, like Song-yi, is distraught at the prospect. Min-joon's powers keep glitching.
Min-joon says he won't leave after all, but Song-yi doesn't know the real reason. Hwi-kyung finally confronts his Jae-kyung, rejecting him as family.
Song-yi finds out about Min-joon's likely death if he stays on Earth. Both Hwi-kyung and Min-joon attempt to force Jae-kyung to turn himself in.
Song-yi insists that Min-joon should return to his planet. Min-joon has dinner with Song-yi's family, and her mom learns he's an alien.
Min-joon professes his love for Song-yi and then vanishes. Over time, Song-yi and others think they catch a glimpse of him, but are they imagining it?