Phil Keoghan Phil Keoghan

The Amazing Race kicked off Season 20 with what Phil Keoghan called the "most bizarre Pit Stop." On Sunday (8/7c, CBS), the season will close with the series' "biggest shocker ever." For the first time, the team who arrives first at the finish line will be turned around for not completing a task correctly. "We were shocked as the viewers are gonna be," Keoghan tells "We were like, 'What just happened?' ... I couldn't believe it happened. Never have we had to tell the team that comes in first that they didn't win the $1 million. But it's good to know we can still have firsts 20 seasons in!" Of course, that team still has a chance to win if they can rectify their mistake at the Roadblock before the next team arrives.

So which team — married couple Dave and Rachel, Big Brother's Brendon and Rachel, border patrol agents Art and JJ, or dating divorcees Vanessa and Ralph — makes the potentially fatal error? Keoghan, obviously, cannot reveal it, but the eyebrow-raising host has plenty to say about the two-hour finale (the fourth place team will be eliminated in Japan, with the final three racing in Hawaii), how he thinks the team screwed up and the cast's excessive bickering.

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