I mean, seriously. Don't be fooled by all the hot shoes and the great sex and the no parents anywhere telling you what to do. Adulthood is responsibility.
Exhaustion begins to take its toll on Meredith. She falls asleep in the shower and she has troubles keeping her eyes open at work. The fact that the nursing home demands her immediate attention to take care of some overdue paperwork for her mom doesn't help either. During open heart surgery with Burke, Meredith has the simple task of actually holding the heart. After the surgery, though, she notices that a fingernail was protruding from a glove and worries that she may have punctured the heart. Should she tell Burke? George points out that had there been a problem, they would've known during the surgery, but there wasn't a problem, the heart is working fine, so telling Burke only risks getting in trouble for something you didn't really do. She opts not to tell Burke, but the issue is still a pressing one for her
George meanwhile has a case of doctor error of his own to deal with fortunately not his error, though. He assists Bailey and Richard on a case where a towel is found inside a woman a towel left in her from a previous surgery five years ago. Bailey orders Cristina to look into the patient's history, to see if she can find out who's responsible. Izzie's boyfriend Hank is visiting Seattle just for the night, so Izzie is planning a really special night just her and Hank and everyone else in the entire hospital. She plans a party at Meredith's that just keeps getting bigger and bigger. Just about everyone gets invited, except, of course, for Alex. To Cristina this is telling Izzie doesn't want to be alone with Hank. But Izzie is in denial, insisting the relationship is still quite strong.
Derek orders Alex to install a central line to a patient with chronic pain problems. Alex ignores those orders when he determines the patient is just a junkie looking for a fix, which doesn't make Derek happy because the first rule in pain management is always to err on the side of caution. He might very well be a junkie, but his pain is very much real to him.
Burke's heart patient, the one that Meredith held the heart for, crashes bedside. They are able to revive and stabilize her, but in a panic Meredith asks if this could have anything to do with her possibly puncturing the heart with a fingernail. Though Burke doesn't think so, her admonition couldn't have come at a worse time the patient's husband is standing right there. He hears Meredith and decides to take legal action. Meredith and Burke must meet with Richard and the hospital counsel the very next morning a meeting that will essentially decide Meredith's fate as a doctor.
Meredith's problems pile up when she finally has to find time to go to the nursing home to officially get power of attorney over her mom's estate. Unfortunately, they don't give her a very big window of time to do it, and it's nearly impossible to get out of work long enough to get there in time. When she arrives, her mother is already "sundowning" and not lucid enough to sign anything in front of Meredith (as needed to be).
Cristina finds a file on the surgery where the towel got left behind, and she sees a familiar name on the roster of doctors: Dr. Preston Burke. She gives the file to Bailey, who gives it to Burke himself. When Cristina asks Bailey what will happen, she's told simply not to worry about it anymore. "It's taken care of." Suspecting a cover up, Cristina is immensely bothered.
Izzie has but one more task to do before she can head home to attend her own party and be with her boyfriend discharge Alex's pain patient. But the pain patient doesn't want to go. He gets in a tussle with the orderlies, bangs his head on some medical equipment, and does severe damage requiring immediate surgery. Derek asks her and Alex to scrub in, to which Izzie can't decline. She winds up missing her own party, having to meet her boyfriend in the hospital parking lot, where they find they don't exactly see eye to eye on their relationship. He wants things the way they've always been, but to Izzie, since she's a doctor now, the top priority has to be the hospital and her patients, and things just have to be different.
Meredith doesn't miss the party. She arrives to find her house overrun with strangers. Initially very upset, she has no choice but to give in after all, she's just hours away from having the fate of her career decided. And that's when Derek shows up. Feeling like she has nothing to lose, Meredith gives in to temptation and she and Derek wind up in his car together, doing what they haven't done since, well the night they met. Unfortunately for the both of them, Derek's car is blocking in Bailey's, and she sees everything. And she lets them know that she saw everything.
The next morning, Meredith attends her meeting, and it does not begin well. Even though it's agreed that the patient's heart was weak because of excessive weight loss and not a puncture from a nail the fact that Meredith said something in front of the patient's husband is considered inexcusable to the hospital lawyers. But it's Burke who stands up for her, using his own mistake five years earlier leaving the towel behind as an example of how a surgeon shouldn't act. To him, she didn't make a mistake being honest about the glove. If only he had been as honest about his suspicions that maybe he didn't check everything properly five years earlier, a woman would not have been found with a towel in her today. Meredith did the right thing that he couldn't do five years earlier. She is put on a short probation, and that's it. Thanks to Burke, her future as a surgeon is not in jeopardy.