Thursday night, the fifth season of Grey's Anatomy concludes with a two-hour finale, officially listed as two separate episodes, "Here's to the Future" and "Now or Never."

Below is a minute-long promo for the gripping finale, in which so much - Izzie's fate, George's future, the MerDer wedding, and a lot more - is hanging in the balance ...

[video url="http://www.tvfanatic.com/videos/greys-anatomy-season-five-finale-extended-promo/" title="Grey's Anatomy Season Five Finale Extended Promo"] [/video]

Follow the jump for the 30-second version which aired after last week's episode, "What a Difference a Day Makes." Looks like a heck of a finale in store for us Thursday ...

[video url="http://www.tvfanatic.com/videos/greys-anatomy-season-five-finale-promo/" title="Grey's Anatomy Season Five Finale Promo"] [/video]

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.