FX is hard at work on a haunting new season of “American Horror Story.” Six separate trailers for the series have been released, but the overall theme of Season 6 remains a mystery to many.

On Tuesday, TMZ was able to obtain photos from the set which suggest that “American Horror Story” will pay homage to an eerie story dating back to America’s earliest days. One photo shows the word “CROATOAN” carved into a tree. As was previously reported, this was the only clue that remained after 117 colonists mysteriously vanished in 1590. It has been suggested that the word was carved there by indigenous people in an attempt to ward off the lingering spirits of the colonists. Fans believe “American Horror Story will center around this story, which is hailed as America’s oldest unsolved mystery, though that has yet to be confirmed.

Those close to production on Season 6 of “American Horror Story” have been tight lipped about all aspects of the show. Trailers provided a glimpse at the theme, as well as the cast, but fans of the series know each season is full of surprise guests and plot twists.

Below is everything we know so far about the latest installment in the “American Horror Story” anthology:

Season 6 is Being Filmed in California:

On Thursday sources told TMZ they had uncovered the “American Horror Story” set deep in the woods in California. The set appeared to be a large, functional colony. TMZ reported that many, if not all, the structures on set were fully furnished as the crew was filming inside and outside.

The crew reportedly spent four long months hammering away on the set, creating structures from the ground up. Photos show several buildings that appear to be houses, as well as a large church.

“American Horror Story” Will Be Partially Set in Colonial Times:

Photos of the structures — as well as the major clue carved into the bark of a tree on set — have us almost certain the theme of Season 6 will be at least partially set in the colonial period. John Landgraf, President of FX, previously revealed that Season 6 of “American Horror Story” would be “principally” set in the present, but feature “echoes of the past.” It is possible that the show will utilize the story of “The Lost Colony” within present day, flashing back to the disappearance of the early English settlers.

The Show May Have Ties To “Murder House”:

During the first season of “American Horror Story,” star Sarah Paulson’s character Billie Dean discussed the story of Roanoke. She explained how all 117 people living within the colony — now known as North Carolina — died unexpectedly and, according to legend, went on to haunt native Americans living in the surrounding areas.

“In 1590, on the coast of what we now know as North Carolina, the entire colony of Roanoke — all 117 men, women, and children — died inexplicably. It became known as the ghost colony because the spirits remained,” she said. “They haunted the native tribes living in the surrounding areas. Killing indiscriminately. The elder knew he had to act. He cast a banishment curse. First he collected the personal belongings of all the dead colonists. Then they burned them. The ghosts appeared, summoned by their talismans. But before the spirits could cause them any more harm, the elder completed the curse that would banish the ghosts forever. But uttering a single word. The same word found carved on a post at the abandoned colony. ‘Croatoan.’”

Several Cast Members Are Expected to Return:

According to TMZ, Angela Bassett and Kathy Bates have shot scenes for Season 6 of “American Horror Story.” Other stars from previous seasons are also expected to appear. Evan Peters, Denis O’Hare, Matt Bomer, Lady Gaga, Cheyenne Jackson and Leslie Jordan are also reportedly taking on roles in the upcoming season. Emma Roberts is rumored to be considering a small role in Season 6, though that remains unconfirmed.

New Stars Will Debut:

Cuba Gooding Jr. is rumored to be making an appearance in “American Horror Story” at some point during the upcoming season. Other newcomers have yet to be named.

“American Horror Story” will return to FX for Season 6 on Wednesday, Sept. 14.

“American Horror Story” Season 6 Photos, trailers and interviews have revealed a lot about Season 6 of “American Horror Story,” which is slated to premiere this September. Photo: FX