This episodes focuses on Meredith's dream of an alternate world in Seattle Grace. In this world, Meredith grew up in a happy, loving household, and Karev is a great, caring doctor. Derek on the other hand, is a lot less desirable. He is not very friendly and doesn't talk to many people. Although, he is still married to Addison. Meredith's mom doesn't have Alzheimer's, is the Chief of Surgery, and is married to Richard.
Bailey is a lot weaker and timid. She is a shy intern at Seattle Grace that goes by the nickname Mandy, who ends up getting fired. Owen and Callie are married with three kids. Cristina doesn't have very many friends and her go-to person is April.
Derek and Addison are not happily married. Addison is pregnant and tells Derek at the end of the episode that the baby is not his. Even in an alternate universe, this marriage ends in a divorce. Owen and Callie's marriage has some speed bumps since Owen is suffering from Post Traumatic Stress Disorder from serving in Iraq. He is speaking to Teddy which is helping him in his recovery. Callie is the Head of Cardio and is mentored by Ellis. We see in an alternate universe that Cristina is very stern and lonely without Meredith.