George has been dating a cute nurse and having a blast doing it ... until he makes a discovery in the bathroom. There's a serious rash breaking out down below. Unsure about its origin, this innocent intern asks Alex for help and he lets George that he has a case of syphillis. Naturally, the entire hospital eventually finds out this secret - and then George learns another one later: the nurse initially suffered this disease through Alex. Ouch.
Throughout this ordeal, Meredith receives a call from the nursing home, asking her to attend the family dinner that night. She claims that she'll try to make it. Meanwhile, McDreamy has been receiving a few secretive phone calls of his own.
Another secret is told to Sheppard - Dr. Webber has a tumor behind his eye and could go blind without surgery. Fortunately, Shep is on the case! He recruits Meredith and Bailey to assist with rescuing the chief's career. While this secretive surgery is going on, Izzie and Cristina are performing an autopsy to determine the cause of death of a patient who suddenly died on their table. Even through it infuriates Bailey because they defied her orders (and the law), the procedure pays off becase they discover a degenerative, possibly hereditary heart condition. The life of the man's daugther is saved as a result.
The life of Dr. Burke's best friend is about to turn for the worse. His wife is pregnant, but it's with another man's child. Burke is the one to relay this news to his recovering pal. He's unaware, of course, that Cristina is pregnant with his child and planning on getting an abortion.
The episode concludes with some good news, some bad news and some awful news: the good news is that Webber's life and career are saved, he can see after the surgery. The bad news, though, is that his first vision is seeing Sheppard comforting Meredith (who admitted her mother's sickness to him). Finally, the awful news - at the end of this difficult day, McDreamy is about to walk to the car with Meredith when a woman walks over to them. Her name is Addison. Addison Sheppard. The last words of the season are: "So, you're the woman who's been screwing my husband?"