The Challenge - Season 18 (2009)

Champions struggle with team camaraderie: Katie and Tonya continue to have their buttons pushed and a past grudge is revealed leading to a shocking departure from Thailand.

The Champions keep up their winning streak and Wes goes after Cohutta in The Ruins.

The Evan, Kenny, Susie, Johanna alliance continues to reign supreme, and Johnny becomes increasingly insecure about his place in the group.

Winding down to the final challenges, the two teams are tied, but the strength clearly lies with the Champions. And the Challengers desperately need a win in order to get rid of their weakest link.

Anger and frustration take hold of the Challengers as KellyAnne and Dunbar wage war over unresolved sexual issues, and Brad makes a decision that could change the course of the competition.

In The Ruins, Dunbar and Kimberly fight to keep the Challengers? dream alive. And, in a strategic move, the Champions consider throwing the next challenge to give them a stronger position in the final. But not everyone agrees.

The Champions become paranoid that they could lose in the end if one worrisome team member fails to pull their weight. The Champions and the Challengers take part in a nail-biting finale - a grueling race for the $300,000 prize!

"The Ruins" cast reunites to dish about the season.

Outtakes and previously unseen footage for the 18th season.