What is er season 12?

Season 12 of ER aired from September 21, 2006 to May 17, 2007. It consisted of 22 episodes and continued to follow the lives and work of the doctors, nurses, and staff at County General Hospital in Chicago.

Some key storylines from Season 12 include the arrival of a new attending, Dr. Gates, played by John Stamos, and his struggles to fit in with the rest of the staff. There are also ongoing storylines involving Dr. Pratt's difficult relationship with his father, Dr. Rasgotra's struggles as a new mother, and Dr. Morris' ongoing battle with his addiction issues.

The season ends with a dramatic hostage situation at the hospital, which puts the lives of several staff members in jeopardy.

Overall, Season 12 of ER was well-received by fans and critics alike, with its compelling storylines, strong performances, and emotional moments keeping viewers hooked throughout the season.