In Grey's Anatomy season 9, episode 16, "This Is Why We Fight," the plane crash survivors race to save Seattle Grace Mercy West from a takeover by Pegasus Horizons. The crisis culminates in a deal with the Harper Avery Foundation,, led by Jackson Avery, to secure the hospital's future. Read the full episode details on the Grey's Anatomy Universe Wiki . Grey's Anatomy Season 9 Episode 16: This Is Why We Fight