There are just two more episodes before the season finale of "Castle", which will possibly end with Castle marrying Beckett.

And if the two finally end up exchanging vows, it is surely not going to be a cakewalk for the lovers, as a shocking surprise in the form of a hustler who shares a complicated past with Beckett is expected to threaten the wedding.

Will this cause Castle and Beckett to call off the wedding?

"Weddings can either go off without a hitch or they can be disastrous," creator Andrew W. Marlowe told TV Guide. "[But] people can end up together after the disaster. We still have a few tricks up our sleeve."

However, a number of fan theories suggest that one of the detectives will be left at the altar. For a while now, the couple has had a smooth sailing relationship and a wedding disaster would be the perfect cliffhanger leading to the next season.

Meanwhile, Monday's episode dealt with the hunt for the best man with both Ryan and Esposito vying for the honor. But Castle remains unaware of the competition between the detectives and he finally chooses his daughter Alexis as the best man.

Seamus Dever, who plays Ryan, told TV Guide that he should have been chosen the best man as he had wonderful ideas for the bachelor party.

"Ryan [wants] to have nice time at the bachelor party,He knows a great place with a great wine list. He's going to be a classy best man, where Esposito is going to be like, 'Yeah, I'm your frat boy!'"

The upcoming episode titled "Veritas" will deal a blow to Beckett, whose investigation into her mother's death goes awry when a man she had put under surveillance gets killed. Evidence points Beckett as the killer of the man and the rest of the episode shows the lovers becoming the targets of a massive manhunt. Meanwhile, "For Better or For Worse" will focus on the wedding.