After a while, the rules of residency become the rules of life. Rule #1: Always keep score. Rule #2: Do whatever you can to outsmart the other guy. Rule #3: Don't make friends with the enemy.
It's Dead Baby Bike day in Seattle the day of an annual bike race with no rules (sponsored by the Dead Baby Bar). This throws off the hospital's entire surgical schedule, filling up the surgical floor with free spirited albeit injured bike messengers, including one named Viper with spokes sticking out of his abdomen. Meredith and Alex both want him, but Viper immediately takes to Alex's handling of the situation Alex just yanks out the spokes and lets him get back to the race, leaving Meredith to suture and do the paperwork. Meredith reluctantly discharges the charismatic Viper, but not before he kisses her in front of a jealous Derek who claims not to be jealous.
The race isn't all just cuts and bruises. There is a casualty. Izzie and Cristina are put in charge of an unidentified visitor to Seattle (has no wallet, just a hotel key card), who was hit by a car when jumped out of the way of the racers. The patient is put on the clock if there's no sign of brain activity in 6 hours, he's to be declared brain dead. This is a very troubling prospect for Izzie.
George gets a special assignment from Richard, attend to a close, personal friend who's been admitted with liver failure. When the male patient makes a pass at George, George becomes paranoid that others in the hospital namely his crush Meredith might think he's gay.
Should Cristina and Izzie's patient be declard brain dead, Izzie wants to make the guy's death meaningful by getting his organs donated. But that's nearly impossible when the person is a John Doe. Cristina wants his organs donated, too, but really just because she wants to be in a harvest. While the man's family is tracked down, though, the patient crashes, needing a blood transfusion as well as surgery to keep his body viable as a donor. Izzie and Meredith do the transfusion, but Burke has to do the surgery, and he doesn't believe in operating on patients that are already dead (the six hours are almost up). So he declines. And without Burke's surgery, it won't be much longer before the heart fails again.
Derek lets Meredith in on a little secret: "You want Burke to do the surgery, get Richard on board first." And they do, by going to George and getting him to tell Richard that they may have a liver for his friend. It works, but not without raising Burke's ire. The surgery is done, the family is tracked down, and now all they need to do is get the patient's wife to agree to organ donation. It's a job that Cristina can't really handle, as observed by Bailey (who shows she can be as thoughtful to patients and family as she can be tough on her interns).
Viper returns, but not for another kiss with Meredith. He's sustained a life threatening injury and Bailey and Meredith have to save him. The prospect of the harvest, though able to give the man's death more meaning, still isn't satisfying to Izzie. She really wanted the patient to wake up, to live. And Burke understands where she's coming from. The bittersweet harvest is done, giving Richard's friend a new liver, and when Izzie comes in to sew up the brain dead guy (who's now just dead guy) so he can be presentable to his family, Cristina sticks around to help, seeing the patient as a human being.