Season 6
The season follows the story of surgical interns, residents and their competent mentors, as they experience the difficulties of the competitive careers they have chosen. It is set in the surgical wing of the fictional Seattle Grace Hospital, located in Seattle, Washington. A major storyline of the season is the characters adapting to change, as their beloved co-worker Stevens departed following the breakdown of her marriage, O'Malley died in the season premiere—following his being dragged by a bus, and new cardiothoracic surgeon Teddy Altman is given employment at the hospital. Further storylines include Shepherd being promoted to chief of surgery, Seattle Grace Hospital merging with the neighboring Mercy West —introducing several new doctors, and several physicians lives being placed into danger—when a grieving deceased patient's husband embarks on a shooting spree at the hospital, seeking revenge for his wife's death.
Episodes
1 Good Mourning; Goodbye Sep 24, 2009 
3 I Always Feel Like Somebody's Watchin' Me Oct 1, 2009 
4 Tainted Obligation Oct 8, 2009 
5 Invasion Oct 15, 2009 
6 I Saw What I Saw Oct 22, 2009 
7 Give Peace a Chance Oct 29, 2009 
8 Invest In Love Nov 5, 2009 
9 New History Nov 12, 2009 
10 Holidaze Nov 19, 2009 
11 Blink Jan 14, 2010 
12 I Like You So Much Better When You're Naked Jan 21, 2010 
13 State of Love and Trust Feb 4, 2010 
14 Valentine's Day Massacre Feb 11, 2010 
15 The Time Warp Feb 18, 2010 
16 Perfect Little Accident Mar 4, 2010 
17 Push Mar 11, 2010 
18 Suicide Is Painless Mar 25, 2010 
19 Sympathy for the Parents Apr 1, 2010 
20 Hook, Line and Sinner Apr 29, 2010 
21 How Insensitive May 6, 2010 
22 Shiny Happy People May 13, 2010 
23 Sanctuary; Death and All His Friends May 20, 2010