India, Oct. 16 -- Grey's Anatomy Season 23 is off to a dramatic start. The premiere, titled Collide, brings a plane disaster, a major hospital shake-up and three big personal developments. Jo Wilson quits Grey Sloan, Simone Griffith discovers she is pregnant and Amelia Shepherd makes a desperate attempt to win Toni Wright back.

The episode picks up about a month after the Season 22 finale. With Owen Hunt and Teddy Altman gone, Grey Sloan is already facing leadership changes. But the opening of its new VIP wing soon creates another crisis. Two planes collide at the airport just as the hospital prepares to celebrate its new Olympic Floor. As doctors rush to treat the injured, their personal lives begin to unravel.

Here's what happened in ...