Grey's Anatomy Season 12 Episode 5
Guess Who's Coming to Dinner
We pick back up with the dinner party at Meredith's house, with the arrival of Callie and her new girlfriend, Penny. Penny turns out to be the doctor who couldn't save Derek.
Meredith tries being nice to her, but has trouble with it. Penny tries to ask Callie to leave, but Callie insists that they stay.
Arizona drinks a little too much and decides that she likes Callie.
Meanwhile, Maggie leaves the party because she has a UTI and worries she needs to see a doctor about other problems.
Alex worries about Meredith acting weird at the party. April takes over for cooking the meal since Maggie has left.
The doctor who attends to Maggie ends up being Andrew. She sends him away, but he returns later with medicine and tells Maggie she should trust him.
Penny tells Amelia the whole story about Derek at the dinner table. Amelia gets angry and tells her to leave. She goes upstairs and yells at Meredith for not telling her about who Penny was, but Meredith says she has no right to be upset.
It also turns out that Penny has plans to start working at Grey Sloan Memorial.
Before Penny leaves, she tells Meredith she's going to put in a request to be assigned to another hospital, but Meredith tells her she'll see her on Monday.