‘Survivor 51’ premieres tomorrow. The Open Era has the twist to end all twists.

After celebrating its 50th season, Survivor is getting ready to usher in a new “era” — and host Jeff Probst means that literally.

Survivor 51 premieres Wednesday on CBS with a two-hour episode, sending a new group of castaways to Fiji to compete for the show’s $1 million prize. The new cast of 21 players ranges in age from 24 to 49 and includes a Grey’s Anatomy actor, a wrestler, a chef and a federal prosecutor.

The season arrives four months after Survivor 50, which reunited former contestants from across the franchise and saw Aubry Bracco crowned the winner in May.

What sets the new season apart is the format. Probst has called it the start of the “Open Era” — the show’s first major reset since 2021. Here’s all you need to know.

What is the ‘Survivor’ Open Era?

The Open Era follows the show’s New Era, which began with Survivor 41 in 2021. The format shake-up is designed to make the game more unpredictable than ever

“The Open Era is taking the massive uncertainty [from Survivor 50] and making it permanent,” he said during the Survivor 50 finale. “The idea is that anything that has ever happened at any time on the show can happen in any season, at any time, in any order — without any warning.”

In an interview with TV Insider, Probst said the season represented a “new type of Survivor game.” He said, “Imagine a giant treasure chest and inside that chest is every single thing we have ever done in 25 years and 50 seasons of Survivor. The question is, each season, what are we going to pull out and put into the season?”

The twist, in other words, is that there is no telling what the twist is.

Probst added, “As an example, just in the premiere, there are seven things from six different seasons, plus three new things in the premiere. So, out of the gate, the players go back to camp realizing, ‘Oh, OK. I get it. It literally could be anything.'”

The Open Era marks another evolution for a show that has repeatedly changed its format. When the New Era began, the game was shortened from 39 to 26 days, and producers moved away from seasons built around specific themes. At the time, Probst told Parade that the aim was to create a “faster, more dangerous and much more intense game.”

But the Open Era presents a different challenge, especially for superfans who think they know Survivor inside and out. Season 51 has plenty of them: new cast member Kristin Flickinger said she has been applying for the show “since the middle of Season 1,” while fellow new contestant Mike Pinsky recalled playing a Survivor-style game with friends when he was 8. Even after studying the game for years, they won’t necessarily know what to expect.

“The superfan may be at a disadvantage now,” Probst said, “because the assumptions that really helped you in previous seasons are your enemy now, because it could literally be anything.”

Will returning castaways compete in the Open Era?

While Survivor 51features an entirely new cast, returning players aren’t necessarily gone for good in the Open Era.

Probst told Variety in May that another season featuring former contestants could happen, although there were no plans at the time. “There’s nothing on the horizon, but they’re very fun to do — for us as well,” he said. “And now we have enough players, we might be able to pull off something that includes returning players sooner than the period of time we had since the last one. But I don’t know. We know what we’re doing for 51 and 52. That’s it.”

Where was ‘Survivor 51’ filmed?

Survivor 51 was filmed on Fiji’s Mamanuca Islands, which have been the show’s home since Season 33.

Speaking at an event in May, Probst said the location was “a logistics issue and not really a creative choice.” He added, “Fiji has actually saved Survivor, and our relationship with their government and all the landowners is amazing. If that changed, we’d be back looking desperately for somewhere.”