Megan Hunt

Megan Hunt is Owen Hunt's younger sister who disappeared when the helicopter she was on went missing while flying through unprotected airspace in the battlefield. She was in a romantic relationship with Nathan Riggs.

Early Life
Megan was three years younger than her brother Owen and grew up in Seattle with her family. The siblings attended medical school together, where they met Nathan Riggs, with whom she became romantically involved.

Disappearance
The circumstances of the day of Megan's disappearance are currently unclear. It is known that she boarded a helicopter, which, while flying through unprotected airspace in the battlefield, went missing, having disappeared without a trace along with her. The events leading to her boarding the chopper, however, are not clear, as both Nathan and Owen have their own versions of the story.

Originally, Nathan told Meredith that he had been working in a field unit with Megan on that day. According to him, they needed to transport a patient, but the chopper only had room for one of them. Megan wanted to go, as the patient was hers, so after failing to talk her out of it, Nathan agreed to let her on board. The chopper, however, never made it. Nathan also pointed out that after Megan's disappearance, he would've continued to look for her, but Owen wanted to give up searching and made him stop.

Upon hearing Nathan's story from Meredith, Owen laughed joylessly, claiming that Nathan never said anything to Megan about not getting on board and, in fact, wasn't even anywhere near the chopper on that day, but with another woman. According to him, Megan had called him earlier that day, telling him that Nathan had been repeatedly cheating on her and that she was getting on the chopper to get away from him. ("I Wear the Face")

Nathan later admitted to Maggie that, although he had told mostly the truth, he did cheat on her and they did fight. He said that he didn't tell Meredith about the fighting and cheating because he believed somethings were meant for just him and Megan, and that he didn't owe anyone that explanation. ("It's Alright, Ma (I'm Only Bleeding)")

Owen later admitted to Amelia that when he learned that Nathan had cheated on Megan, he had told her to get on the helicopter. It was the last thing he ever said to her. ("Trigger Happy")

Nathan Riggs
Megan and Nathan were in a romantic relationship, and Megan apparently loved him dearly. However, according to Owen, Nathan had been cheating on her, prompting her to get on the chopper along with which she disappeared. ("I Wear the Face")

Owen Hunt
Owen does not talk about Megan to her friends and co-workers, but has revealed that they were very close and she used to follow Owen and do everything he did. He described her as being smarter, funnier, and a better person than him.

Notes and Trivia

 * Megan's disappearance and the preceding events are the reason for Owen and Nathan's current feud.