Ed Middleton is ecstatic: he's just got engaged to his girlfriend, Sam, and he couldn't be happier. At least, hethinkshe's engaged. The thing is, it was Sam who did the proposing, and the more he thinks about it, the less he's sure that she was actually asking him to marry her. She could have just been asking the question, you know...hypothetically.
As the wedding day draws nearer, Ed becomes more and more uneasy. Sam keeps disappearing off for furtive meetings and private phone calls, and when he spies her going into a pub with a man he's never seen before, all his old jealousies and insecurities threaten to re-surface. It's the perfect time for Ed's unhinged ex-girlfriend, Jane, to show up on his doorstep.
Meanwhile, Dan - Ed's best-friend and soon-to-be-best-man - is determined to throw him a stag night to remember. And when a severely hung-over Ed wakes up the morning after the night before to see a second dent in the pillow, it seems as if Dan has got his wish.
Will Ed manage to find out the truth about his stag night as well as the identity of Sam's secret man? Or will an accidental proposal lead them both down the aisle to a wedding neither of them ever imagined?