"Somebody That I Used To Know" is the tenth episode of the tenth season of Grey's Anatomy and the 206th produced episode of the series. It is also the 317th produced episode of the Grey's Anatomy franchise. It was broadcast on November 21, 2013.
Tensions continue to rise between Cristina and Meredith when they find themselves fighting for their own careers at the expense of their friendship, while Cristina grows closer to Shane as she tries to escape her troubles with Meredith and her unease with Owen's attempts to move on. Meanwhile, Owen tries to organise a Thanksgiving dinner for him and his girlfriend which quickly grows out of control while Ben worries that a conversation with Derek could have dire consequences for Bailey when he confides about Bailey's obsessive tendencies. Callie and Arizona navigate their tenuous reunion, but things grow complicated when the truth about Arizona and Leah's history comes to light while April's upcoming nuptials cause Stephanie to question her relationship with Jackson. Elsewhere, desperate to get out of his hospital bed, Richard pushes himself too far towards recovery.
- "The body is an infinity complex mass of interacting systems. People like to think doctors see it all clearly but it's not always obvious what's a hiccup in the system and what's a full on medical disaster. We figure that out in our first year of residency and spend the rest of our careers lying about it."
- "It's just a cold, muscle through it. It'll pass. Nothing's really wrong. We're doctors, we'd know if something was wrong. We'll be fine. Nothing's wrong."
- "Differentology" - Bunji Garlin
- "Moon" - Sleeping At Last
- "Romeo" - Until The Ribbon Breaks
This episode's title originated from the song Somebody That I Used To Know, originally sung by Gotye.