It's the morning of the biggest day of his life... and Barney Stinson is passed out with a world class hangover.

Can Robin and Lily get him to "Rally" before the ceremony? Will Lily remember Barney's ridiculous recipe for his Stinson Hangover Fixer Elixir in time to save him? Or will Robin simply drown him and be done with it?

Check out these preview photos from How I Met Your Mother Season 9 Episode 18. They depict Robin and Lily taking desperate measures to rouse the drunken groom.

Don't forget, you can always watch How I Met Your Mother online right here at TV Fanatic. ENJOY!