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.
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 Eps9Greys Anatomy - Season 1
: Addison Montgomery-Shepherd arrives, revealing Derek is married. The season one finale of Grey's Anatomy ,
Derek froze, his face draining of color. "Addison. What are you doing here?" titled "Who's Zoomin' Who?