Credit: Monty Brinton/CBS

Something was fishy when I arrived in the Philippines the day before the filming began to interview the 10 pairs set to compete in Survivor: Blood vs. Water. Namely, the fact that one of them was missing. RC Saint-Amour (from Survivor: Philippines) and her father Craig, who were supposed to be one of the dynamic duos, were nowhere to be found. And the other contestants were just as confused as I was. RC and her dad had indeed traveled over to the Philippines with the other cast members, and were staying at the same pre-game location with them. Then, all of a sudden, they were gone.

Nobody was sure where they had gone or why. Were they coming back? Were they alternates that had been sent home? Had they violated some sort of rule? All the other players knew is that they were now down to only nine couples competing in the game. But not for long. At the end of the day, just 24 hours before the show would start filming with its new Day Zero twist, a new couple arrived on the scene — Candice Cody (formerly Candice Woodcock from Cook Islands and Heroes vs. Villains) and her husband John.

The other shocked contestants — who got their first look at the new couple when they were brought in for the group cast photo — had just encountered their very first twist in the most twist-heavy season in Survivor history. In the video interview below, host Jeff Probst reveals exactly what happened, and why RC and her father were pulled from the game right before filming began. “We had our 10 pairs out here and we were good to go,” says Probst. “We got out here and RC and her father Craig — who we loved and wanted back on the show, RC for obvious reasons. Her dad is just as good. But when our doctors were checking them, medically his blood pressure was very high. And it was so high that we had to pull him from the game.”

Then it was a race to get Candice and John all the way from Washington, D.C. to a remote corner of the Philippines in time. “I emailed immediately to [casting director Lynne Spillman] and said ‘they’re out, we need them’. Within, I don’t know, an hour later, we knew what flight they were on, what time they were gonna arrive, we had the chopper over there to pick them up, It’s a whirlwind, but that’s Survivor.”

It’s unlike anything I’ve ever seen before in all the times I’ve been on location covering the show. How will the last minute deletion of RC and her father, and the addition of Candice and her husband affect the other teams? And does coming in late after all the other teams had arrived put the newcomers at a disadvantage? We’ll find out when Survivor: Blood vs. Water premieres with a special 90 minute episode on Sept. 18. But to hear more from Jeff Probst on the big last minute switch, click on the video player below.