- There's a new addition to the Meredith house: Derek Shepherd. At the end of season 4 the two of them got back together. Naturally they decide the next step is for Derek to move in. In the beginning Meredith doesn't deal with McDreamy being in her house so well, but it doesn't take long for her to come around.
- Some tension builds between Cristina and Meredith. Meredith is annoyed Cristina keeps getting the good surgeries and Cristina is so sick of listening to Meredith drone on and on about Derek. It gets so bad that at one point BFFs Cristina and Meredith stop talking to each other.
- Enter McMommy. Meredith gets a bit nervous when Derek's mother visits town. Meredith puts on a forced smile and pretends to be someone she thinks Derek's mother would like. She should have known that she is perfect just being herself.
- Derek finally asks Meredith to marry him. They end up having an impromptu ceremony that includes scribbled vows on a blue post-it. As hard as it is to believe, the ceremony is way more romantic than the proposal.