: Izzie and Cristina risk their careers to find the truth about a patient's death.
: Addison Montgomery-Shepherd arrives, revealing Derek is married. Eps9Greys Anatomy - Season 1
Meredith Grey spent the day feeling like her relationship with Derek Shepherd was finally on solid ground. They had survived the initial awkwardness of their secret romance and the pressures of the internship. But at Seattle Grace Hospital, peace was always temporary. A syphilis outbreak had swept through the staff, forcing the Chief to hold a mandatory—and humiliating—meeting about sexual health. George O’Malley was the most public victim of the "syphilis train," having contracted it from Olivia, the nurse who had caught it from Alex Karev. : Izzie and Cristina risk their careers to
: A "syphilis train" starts with Alex and spreads to Olivia and George. They had survived the initial awkwardness of their
: Derek operates on Chief Webber's brain tumor in secret.
The episode ended on Meredith’s shocked face, leaving fans to wait months for the fallout of the revelation that "McDreamy" was actually a married man. Key Storylines from the Finale