Greys Anatomy - Season 12 -

'Grey's Anatomy' Season 12 Trailer: "Everything Has Changed"

: Miranda Bailey successfully campaigns to become the hospital’s first female Chief of Surgery . Greys Anatomy - Season 12

: Their developing romance culminates in a wedding in the season finale, though Amelia initially has doubts and runs away before the ceremony. 'Grey's Anatomy' Season 12 Trailer: "Everything Has Changed"

: This season marked the final regular appearance of Sara Ramirez as Callie Torres. Reception & Ratings Reception & Ratings : The couple's marriage collapses,

: The couple's marriage collapses, leading to a divorce. However, they discover April is pregnant shortly before signing the papers.

: A bitter custody battle over their daughter, Sofia, ensues when Callie plans to move to New York with Penny.

: Tension peaks when Callie’s new girlfriend, Penny, is revealed to be one of the doctors who failed to save Derek. Penny eventually joins the hospital as a resident, causing friction with Meredith and Amelia. Relationship Turmoil :