Here is how the twist works. You are partnered with someone from the opposing tribe. You can communicate with them here at the arena in a private confessional that the two of you will share. We will never reveal who is partnered with whom, it is up to you whether or not you want to reveal that information to your tribemates.
The last partnership remaining in the game will receive one Immunity Talisman each. The Immunity Talisman is good up to and through the final 5. It differs from the Hidden Immunity Idol in that it must be played before the votes are cast at the beginning of Tribal Council. It is essentially a hidden immunity necklace that can be saved and used at any Tribal Council you'd like. This may not seem very valuable now, but towards the end of the game, when there are only a few people left and 2 of them suddenly have Individual immunity and you do not, it will be a huge deal.