All the residents except for Meredith are shunning Cristina, now that her secret is out. George is particularly bitter because she was willing to let Burke operate on his father. The Chief won't punish Cristina and Burke, much to Bailey's dismay. The Chief orders Burke to get his hand fixed but Burke tells Derek he doesn't want another surgery, implying that his tremor is all Derek's fault.
Meredith tries to convince a distraught Ellis that Richard's leaving her happened years ago. Ellis says it's all because she had a daughter and that she should never have had children.
Miranda comes up with her own punishment for Cristina, assigning her to assist Dr. Hahn with Mr. O'Malley's surgery. The other interns complain that it's not a punishment at all, until she shows them the other case she wants their help on: Two conjoined twins who want to be separated.
The separation surgery is going to require 22 doctors, including Mark, Derek, and Miranda. Burke's blaming him shakes Derek's confidence, and he refuses to do the surgery, claiming it's too dangerous because both twins could end up paralyzed. Miranda confides to Derek how Burke's bumping her from his surgery made her question her own ability. She tells Derek she knows he can pull off this surgery.
Izzie is assigned to help Mark prep for the surgery, but the only thing he wants her to do is get his coffee. She tells him she won't respect him until he does something worth respecting. During the twin separation surgery, Mark unexpectedly requests that Izzie scrub in, which doesn't sit well with Miranda, who's upset that Cristina is also performing surgeries.
Derek completes his part of the surgery and both twins are fine. Everyone applauds as the two gurneys are wheeled apart.
The Chief loses it when Burke says he blames Derek for his tremor. He tells Burke that he let him down, and that if he doesn't let Derek fix his hand, he's letting himself down.
Prior to his Mr. O'Malley's surgery, George questions Dr. Hahn's methods and since he won't let it drop, Miranda orders him to stay 50 feet away from his father at all times.
He immediately disobeys and goes to see his father. Mr. O'Malley says that George is mad at everyone lately, but that George is really mad at him, because he smoked and drank and brought on the cancer. George's brothers show up then and start saying, "You're going to get in trouble, Georgie." He's yelling at them not to call him that when his father stops breathing. It looks like a heart attack, but his heart is just going too fast. Burke appears and calmly guides him through the steps necessary to get Mr. O'Malley breathing normally again.
George, against orders, is watching the surgery on his father. Burke, who isn't supposed to be there either, joins him. George can't bring himself to watch, so Burke narrates what's happening. When there's a complication, George turns to see Dr. Hahn let Cristina do her running loop stitch. Burke assures him that she knows what's she's doing and he's right, George's dad pulls through the surgery with flying colors. Burke says that he wouldn't have done anything differently than Dr. Hahn. He seems to be talking about himself when he says you never know how someone will respond to surgery. As he goes to leave, George thanks him.
Miranda tells Richard that not punishing Burke and Cristina undermines her authority. She points out that the common thread between Izzie causing Denny's death and Cristina's deception is her. Richard assures her that she raised them well and that they made mistakes. But he praises Cristina for reporting on her boss and boyfriend, saying how much she's grown.
Addison recruits a reluctant Meredith to help with her half sister Molly, who is in the hospital for a C section. Complications with the baby mean that it has to be delivered prematurely. Susan, her father's second wife, says she hasn't yet told Molly about Meredith.
The baby isn't breathing and Meredith, mesmerized by the sight of the unmoving baby, freezes when Addison tells her to talk Molly through it. Addison has to operate but Meredith's hesitation in the OR means she's not scrubbing in and instead must keep Susan and Molly updated on the baby's condition.
Meredith informs Susan the baby's going to be okay and Susan hugs her. Meredith says she doesn't consider them her family and walks away. But when she sees them holding the baby, she watches wistfully. Susan tells her they can be her family if she wants and she doesn't answer.
In the locker room, Meredith yells at everyone for judging Cristina. She reminds Izzie how she cut Denny's LVAD wire and how they all covered for her and how Izzie helped Alex study for his boards, even after he cheated on her. They sheepishly admit they were wrong, all except George, who walks out. Cristina wants to know why Meredith keeps standing up for her, and she says, "You're my sister, you're my family. You're all I've got."
Derek tells Meredith he'll be late since he's going to be looking at Burke's shoulder. Cristina hesitates, then gets in the elevator with them.
Listening to her mother rant again about how she shouldn't have had children, Meredith simply hugs her, a simple action getting through where no words could.