John O'Brien

Everyone seems to know who the father of Rachel's unborn baby is except for the man himself: Ross. When he finds out, he is more concerned with other matters than his relationship with Rachel. Meanwhile, Phoebe and Joey fib about a gas leak to gain entry to Monica and Chandler's apartment.

After taking a loan from Evelyn, Alan is guilted into double-dating with her, her new romantic interest and his daughter.

Some very deep secrets are made painfully public when Meredith's mother, who suffers from Alzheimer's disease, is brought to Seattle Grace for a surgical procedure. Meanwhile, some frightening news about Cristina's health is brought out into the open.

After a successful operation on his heart, George's father undergoes surgery for his cancer, Thatcher Grey visits Seattle Grace in order to see his new granddaughter, and Meredith discovers that Derek has trouble sleeping soundly. This is Part One of a two-part episode.

A mysterious stalker from Adam's past appears on Wisteria Lane; Bree and Orson encounter marital problems with a new baby in their lives; Lynette reunites with her long-lost stepfather.

The interns deal with a family involved in a car accident, Derek lets his emotions get the best of him, and Burke and Izzie make a new suggestion to Denny.