Eps9greys Anatomy - Season 1 -

: Addison Montgomery-Shepherd arrives, revealing Derek is married.

The season one finale of Grey's Anatomy , titled "Who's Zoomin' Who?," originally aired on May 22, 2005. The episode is famous for its massive cliffhanger: the arrival of Addison Montgomery, Derek’s secret wife. Eps9Greys Anatomy - Season 1

The woman turned her gaze to Meredith, her eyes sharp. "And you must be the woman who's been sleeping with my husband." The woman turned her gaze to Meredith, her eyes sharp

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 : Izzie and Cristina risk their careers to

: A "syphilis train" starts with Alex and spreads to Olivia and George.

: Izzie and Cristina risk their careers to find the truth about a patient's death.