The two-hour “Amazing Race” finale promises to be the most shocking finish ever. 

In a short preview for Season 20’s final episode, which airs Sunday, May 6 at 8/7C on CTV, host Phil Keoghan is shown at the finish line saying: “You are the first team to arrive. However, you have not completed the Roadblock and you must complete the Roadblock before I can check you in.”

It’s a historic finish where a “colossal mistake could cost one team a million dollars,” he says.

Watch a preview of the finale here.

The four remaining teams – Dave and Rachel, Art and JJ, Vanessa and Ralph and Brendon and Rachel – will first race through Japan before travelling to Hawaii where one team will take home the top prize.

So who is going to cross the finish line first?

Dave and Rachel: The married couple has been the most consistent of all the teams and with six first-place finishes, they are definitely the team to beat. But their constant bickering may get in the way. In the preview, we see Rachel telling Dave: “You’re driving me insane.” He replies by saying, “Silence is golden,” only to have Rachel come back with: “Then why don’t you shut the (bleep) up.” Looks like things are about to get even tenser…

Art and JJ: The two friends and border patrol agents have also been strong contenders throughout the “Race,” arriving at the Pit Stop first three times and finishing in the top three every other leg except one. The team had a previous alliance with Dave and Rachel, but ended it after the married couple failed to U-turn competitors Brendon and Rachel. The guys have an advantage when it comes to physical strength, but as we saw in the last episode during a time-consuming challenge that involved sifting ginger and transporting it to a warehouse, it doesn’t always help. Art calling JJ “a little bitch” also didn’t help.

Vanessa and Ralph: Although these dating divorcees never had a first-place finish, they have managed to make their way into the final four. They’re also a strong physical team but Vanessa faltered on the last episode when she tripped and hurt her ankle. Along the way they’ve also been knee-deep in drama with Brendon and Rachel but the two teams finally called a truce at the last Pit Stop in India. If either of these teams want a shot at winning, they’d be wise to take that to heart and focus on keeping their heads in the game.

Brendon and Rachel: The engaged couple, who competed and met on reality series “Big Brother” (Rachel even won the $500,000 grand prize), have been despised by many of the other teams, who didn’t feel it was fair for them to be competing on “The Amazing Race.” Dodging the trash talk has only spurred this couple on and the only thing that could possibly slow them down is Rachel’s free-flowing emotions. In the preview, we see her scolding Brendon for not listening to her when they didn’t make it onto a bus with the other teams. Every other team may have discounted them as serious contenders, but Rachel, with Brendon’s unwavering support, outwitted every other person in the “Big Brother” house to take home the grand prize, so I wouldn’t count them out just yet.

But trying to figure out who is going to cross the finish line first may be a moot point, now that we know that this team will have to go back and complete the Roadblock before they can check in. I guess the real question here is, who is poised to become the second place team? And will they be able to snatch away the million dollar prize?

We’ll have to tune in to find out.

“The Amazing Race” Season 20 finale airs Sunday, May 6 at 8/7C on CTV. Full episodes are also available online at CTV.ca.

About Sheri Block

Sheri Block has been covering entertainment for CTV.ca since 2008. In addition to covering Will and Kate’s Royal Wedding in London, Sheri’s highlights have included going on tour with “Canadian Idol,” being a stand-in on “Canada’s Next Top Model” and meeting Colin Farrell at the Toronto International Film Festival.Follow her on Twitter!