Warning: spoilers ahead for the "Uncharted" episode of Outlander Season 3 AND the Voyager novel in the Outlander book saga.
Outlander kept Claire and Jamie separated in different centuries for the first half of Season 3, and the second half has seen them split apart yet again after a British captain kidnapped Claire to take advantage of her medical expertise. While on the British warship, Claire discovered that warrants for murder and high treason had been issued against Jamie and she would be used as bait to lure him to Jamaica; unwilling to let Jamie be captured and almost certainly killed, Claire jumped overboard in a desperate attempt to reach land and reunite with Jamie. In "Uncharted," Claire did manage to reunite with Jamie, but she also stumbled on a time travel clue that will change the course of the series forever. Book readers know where the story is likely going, but could the show change it?
Here's what happened. "Uncharted" saw Claire wash up on the shores of Saint-Domingue -- a.k.a. Haiti -- after her desperate jump from the Porpoise, and she encountered a disgraced (and distinctly loopy) priest by the name of Father Fogden, who advanced a plot introduced in an earlier episode by Margaret Campbell: the mystery of Abandawe. Fogden obtained a jar of beetles from a cave called Abandawe, and he had this to say:
Voracious little fellows from a sacred cave called Abandawe. It is hallowed to the natives of Jamaica. A place of great power. It is said that folk disappear there.
Father Fogden's description of Abandawe sounds an awful lot like the standing stones at Craigh na Dun, where Claire passed through time a few times in the series so far. Earlier in Season 3, purported seer Margaret Campbell told Claire that "Abandawe will devour" her. Now, in the Voyager novel, none other than the not-so-dead Geillis Duncan/Gillian Edgars did venture to Abandawe with the intention of traveling through time, and Claire arrived just in time to complicate things for her. It's a key part of the book and the saga as a whole, but we have to wonder: could the show go in a different direction and send Claire through time again?
Geillis hasn't been a part of Season 3 to date, and there are only two episodes left. If she turns up and suddenly has a huge role, it might feel out of the blue. Claire has struggled with being separated from either Jamie or Brianna by two centuries all season; it stands to reason that perhaps something could motivate her to return to the 1960s for the sake of her daughter. The Season 3 opening credits indicate that some more supernatural shenanigans are likely on the way before the end, and there's precedent in Voyager for Claire kinda sorta hearing from Brianna even while stuck in the 18th century. Could she travel through Abandawe to return to Brianna? Margaret did say that Abandawe would devour her, and it's not like Claire will die in Season 3 when there's a Season 4 on the way...
That said, it's possible that neither Geillis nor Claire will travel through Abandawe, even if Geillis does appear before the end of the season. If Ronald Moore goes off-book, he could theoretically bring Roger or Brianna into the mix in the past. The Season 2 finale indicated that the children and descendants of time travelers can also pass through places like Craigh na Dun, and both Roger and Brianna heard the buzzing that accompanies passage through time while at the standing stones.
Admittedly, Outlander has been largely accurate to the novels to this point, and viewers were told before Season 3 even started that the next batch of episodes would be mostly faithful. That said, nobody behind-the-scenes would spoil such a huge twist as a Claire/Geillis switcheroo at the end of the season, and it's possible that showrunner Ronald Moore wants to put his own twist on the magic of the grand story. Readers might not be entirely happy with such a huge departure from the source material, but anything can really happen in a tale about time travel.
All things considered, the odds are quite good that somebody will be traveling or attempting to travel through time via Abandawe, and we can bet that Claire will end up at that place sooner rather than later. Surely she couldn't leave the West Indies without visiting Abandawe when she's so close, and there are still two full episodes in Season 3 before we're stuck in another hiatus waiting for a new season. Whether Geillis or Claire or somebody else is the time traveler in question will remain to be seen.