What did Mellie know? What might Hollis Doyle have done? And, oh yeah... WHO SHOT THE PRESIDENT?

That is the major question Scandal fans have on their mind following "Defiance," an episode that ended in truly shocking fashion, even for a show that twists its audience into knots at the conclusion of almost every hour.

The answer to that pressing inquiry will be revealed next Thursday night. So promises this trailer for "Happy Birthday, Mr. President." Who is the gunman? Take your best guesses now and hit Play:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.