<em>Grey's Anatomy</em> Grey's Anatomy

Happy 250th episode, Grey's Anatomy! On second thought, maybe "happy" isn't exactly the right descriptor for this installment, but it was certainly an eventful one.

We pick up right where last week's episode left off - with Meredith (Ellen Pompeo) opening the door only to realize that Callie's (Sara Ramirez) new girlfriend Penny (Samantha Sloyan) is none other than the doctor who basically admitted that she was responsible for Derek's death. Meredith quickly saves face and offers Penny a warm welcome, but that doesn't last long.

While Amelia (Caterina Scorsone) and a post-coital Maggie (Kelly McCreary) flutter about, trying to make last-minute preparations for their dinner party, Meredith's panic level starts to rise - as evidenced by the fact that she's being nice to Jo (Camilla Luddington). But Alex (Justin Chambers) is the only one who notices that something's wrong. Everyone else is basically oblivious to the tension and excited to meet Penny - even Arizona (Jessica Capshaw), who has managed to chug an entire bottle of wine by the time Callie and Penny show up.

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Meanwhile, Meredith has sequestered herself in the bathroom upstairs, dry-heaving and having flashbacks to the night Derek died. But her panic attack is interrupted by a UTI-plagued Maggie, and then by Amelia, who's frantically looking for her co-hosts. Germaphobe Maggie is freaking out about whether something more than a UTI has infiltrated her "clean house," and decides to head back to the hospital to find out for sure. Turns out, the doctor who's assigned to her is none other than Andrew (Giacomo Gianniotti). So much for avoiding awkwardness by leaving the house.

As Penny and Arizona bond (no, really! Arizona thinks she's "a delight," and possibly wants to date her), Jackson (Jesse Williams) arrives and has an awkward run-in with April (Sarah Drew). And Stephanie (Jerrika Hinton) gives Jo the evil eye for ratting her out to Amelia last week - and then proceeds to flirt with Jackson in front of April, who takes charge in the kitchen since none of the dinner party hosts know how to, you know, cook. What a party!

Callie, who's on call, gets summoned back to the hospital, and forces Penny to stay at the party without her. (Does anyone else think this seems a little implausible?) Meredith quietly lays out some ground rules, including that Penny can make small talk with anyone there except for Meredith, and will leave immediately after dinner so that Meredith will never have to see her again. Which is all well and good until ...

We learn that Penny is a new resident transfer who's joining the program at Grey Sloan (and also that she calls Callie "Calliope," just like Arizona used to). It's still unclear whether Arizona is jealous of or crushing on Penny ("Find a Penny, pick it up!" she drunkenly quips), but as Penny's work history starts to reveal itself, Meredith can't contain herself any longer. "Perfect Penny killed my husband," she finally blurts out, before getting up and walking away from the table, leaving everyone in stunned silence.

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Callie, of course, bursts through the door with Owen (Kevin McKidd) right at this moment, just as Amelia is demanding to know exactly what happened the night Derek died. Penny sputters that the hospital was understaffed, and she should have insisted that he get a CT, and Amelia continues her interrogation until Callie puts a stop to it - but not before ordering Penny out of the house.

Amelia storms upstairs to yell at Meredith for not telling her who Penny was from the get-go, and Meredith has a near-breakdown. They get into a screaming match, with Meredith telling Amelia that she lost her husband and the father of her children (where areMeredith's kids during this dinner party, anyway?) that night.

Callie, meanwhile, can't believe that Penny didn't tell her the truth. "I didn't know if you knew him," Penny says feebly. "It was the worst night of my life." R.I.P. Calliopenny? Maybe not, as Callie later tells Jackson that she's not sure how to "shut off" her feelings for her new squeeze.

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After dragging her out of Meredith's room, Owen tries to talk Amelia off the ledge. When she asks him why he's always so calm and perfect all the time, he confesses that he's not. For instance, after the plane crash, he assumed Cristina was dead and felt relief - because he always knew on some level that she'd leave him and he would have preferred to have their relationship frozen in time. That's pretty heavy stuff right there, even for Grey's. But the conversation ends with Amelia and Owen cuddling, so that's something.

All is definitely not lost. April and Jackson do the dishes together and he compliments the dinner she made, and Jo and Stephanie make up after Jo offers a sincere-sounding apology - but then get in a fight again when Stephanie is offended by Jo's assumption that her difficult childhood is why she's a good surgeon. Back upstairs, Meredith and Alex crack open a bottle of tequila. (Um, okay really, where are the kids?)

At the hospital, Andrew gives Maggie her UTI medication, and they bond over how much dating sucks. Maggie, like myself, has trouble believing that Andrew has any trouble with the ladies, but let's go with it. He assures her he's clean, but if I were Maggie I'd wait for those test results regardless.

No one can find Penny, because she has inexplicably gone back into Meredith's house. With everyone else gone, Meredith and Penny are left face to face in the entryway. Penny tells Meredith that she's going to file a request the next day to be transferred to another program, but Meredith's not having it. "I'll see you Monday," Meredith tells her. "Don't be late."

We've got two weeks to wait before we get to see Penny's first day, but the preview indicates that it's going to go less than swimmingly.

What did you think, Grey's fans? How do you feel about the Penny plot twist? Did Meredith and Amelia overreact? Are you liking Maggie and Andrew together? And seriously, where the hell are Meredith's kids? Sound off in the comments!

Grey's Anatomy airs Thursdays at 8/7c on ABC.

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