Let’s be honest with ourselves: No one’s watching the time-traveling romance drama Outlander for a scientific exploration of how time travel could possibly exist. Viewers are here for the romance; we know it, the show knows it.

Outlander, which is based on Diana Gabaldon’s popular series of novels, is much more focused on what happens when our heroine Claire (Caitriona Balfe) travels from 1945 back to 1743 and meets Jamie Fraser (Sam Heughan), the Scottish highlander who turns out to be the love of her life, rather than how she does it. Still, it’s hard to watch a TV series with that kind of premise and not wonder. That’s why we’re here to help! Below, find some answers—and, not surprisingly, even more questions—to the who, what, where, when, why, and yes, how of time travel on Outlander.

Who can time travel on Outlander?

Apologies to all of those hoping they could just touch some stones and find a kind, hot person waiting on the other side, but according to Outlander, the ability to time travel is genetic. This comes into play in Season 5: Claire’s daughter Brianna (Sophie Skelton), who inherited the time travel gene from Claire, and Roger (Richard Rankin), a descendant of the time-traveling Bakra herself, Geillis Duncan (Lotte Verbeek), are ready to head back to their time—but haven’t figured out if their son Jemmy (Andrew Adair/Matthew Adair) can time-travel or not. Eventually, they discover that Jemmy hears the same buzzing noise they hear when near certain stones, meaning that he can travel, too. (With a genetic makeup like that, how could it have ever been in doubt?) We still don’t know who the first time traveler in Claire’s lineage was, or how it came to be, but other travelers we’ve met include Wendigo Donner (Brennan Martin), Otter Tooth/Robert Springer (Trevor Carroll), and Master Raymond (Dominique Pinon).

Can a time traveler affect the past on Outlander?

Honestly, not much. Although not exactly confirmed, it seems Outlander takes a real Lost approach to people hopping around time, in that “what happened, happens.” Claire and Jamie try to stop the tragedy of Culloden but can’t do much about it. Robert Springer and his cohorts may have traveled back to stop the massacre of Native American tribes, but they find themselves helpless to do anything to prevent it. Claire might know what the future holds, but she is powerless to do anything except ride it out. This becomes especially stressful as the Revolutionary War comes knocking at the door of Fraser’s Ridge in Season 5.

Where can a person time travel on Outlander?

It’s best to start at the beginning: Craigh na Dun. In 1945, our heroine Claire Randall-soon-to-be-Fraser comes upon an ancient stone circle located outside of the town of Inverness in the Scottish Highlands. There’s lots of chatter about strange things happening there and rituals going on—real mystical type stuff. Well, the chatter is real. Claire finds herself inexplicably drawn to these stones, and when she gets close enough, she hears a loud buzzing. When she puts her hand on one, well, you know what happens next: Claire is transported to 1743, where she meets a very handsome Scot.

These stones come into play time and again on Outlander: Claire travels through the stones at Craigh na Dun in 1746 when Jamie brings her back to them in order to keep their baby safe, and then one more time in 1968 when she travels back to be reunited with her one, true love in 1766. The stones actually get a lot of use in 1968: That’s when fellow traveler and major thorn in Claire’s side (to say the absolute least) Geillis Duncan goes through the stones in hopes of making the Jacobite uprising a successful one, Brianna travels through Craigh na Dun after she finds an obituary from the 1770s that says her parents die in a fire, and Bree’s bearded boyfriend, Roger, follows her soon after.

Related: Is Outlander Historically Accurate? Author Diana Gabaldon Tells Us What She Thinks of the Show’s Blend of Fact and Fiction 

But Craigh na Dun isn’t the only stone circle having all the time travel fun: Claire comes across two other locations where time travel is possible. The first is during Claire and Jamie’s Season 3 sojourn to Jamaica where she bumps into Geillis again; through Geillis’ nefarious plans to travel back to their present-day in order to murder Brianna (it’s a whole thing), Claire finds the Abandawe cave sitting under a stone circle with a pool of water that acts as a time travel portal. Then, once the Frasers settle in America, they come across the Ocracoke stone circle in North Carolina, which Brianna, Roger, and son Jemmy attempt to use to get back to their own time at the end of Season 5. It doesn’t work, which leads us to…

How does a person time travel on Outlander?

Outlander’s version of time travel isn’t an exact science. Once a person with the genetic ability is at one of these specific locations amenable to travel and they hear the buzzing, there are a couple of theories as to how a traveler can cross through.

The one thing everyone can agree on: A traveler needs some sort of gem to go through the stone. The first time we see Claire travel in the pilot episode she doesn’t seem to have a gem, but in Season 3, the show retcons a little and Claire explains to Brianna that she was wearing a jeweled watch. The second time Claire travels to escape the horrors going down at Culloden, they make it a point to show Jamie giving Claire her father’s ring with a gemstone—a stone that is missing once Claire travels through. Executive Producer MarilDavis confirmed the importance of this element to IGN, saying, “You’ll notice in [Season 2], the ring that [Claire] goes through with Jamie, the gemstone is gone. That seems to be another consistent rule to get through so you don’t kill yourself.”

We see all of the travelers using gemstones to make safe passageways through time. But there are other theories, too. Geillis Duncan makes it known that she believes a person must not only have gems to travel, but a blood sacrifice. When Claire, Bree, and Roger find her going through the stones in 1968, they also find her very-much-murdered husband burning nearby. When Geillis makes an attempt to go through the portal in Jamaica at the end of Season 3, she is planning on using Young Ian (John Bell) as her sacrifice. She’s honestly shocked to hear that Claire didn’t need to do any murdering at all in order to get through the stones safely.

Not like that’ll stop her: “A girl can’t be too careful” she tells a horrified Claire.

So if Claire isn’t adding blood to the mix, how is she safely traveling? The show doesn’t get into this too much, but Geillis is surprised that Claire has traveled so many times and survived, which might be something that comes into play later. In the meantime, Claire believes it has “something to do with the person on the other side, drawing you to them.” And it seems Claire might be onto something there…

When can a person time travel to on Outlander?

After all, how is it that Claire travels through the stones at Craigh na Dun in 1945 and winds up 202 years in the past, Geillis travels through the same stones in 1968 and lands in the 1730s (remember, she’s well established in town when Claire first meets her outside of Castle Leoch), and then Claire, Brianna, and Roger all travel from that spot around 1968 and follow the 202-year rule once again? Well, Outlander is a little iffy on explaining the inconsistency, but Claire’s hypothesis that you’re drawn to someone who pulls you to that time would mostly do the trick. She and Jamie’s love is so strong, so otherworldly, that he pulls her to 1743 before they even meet. Bree would be pulled to a specific time by her parents, and Roger by Bree.

At the end of Season 5, when Bree and Roger attempt to travel back to their own time with Jemmy and wind up exactly where they started, they both admit that they were thinking about “home” and since all of their family is in the 1770s, it would make sense that they landed there again. It seems time travel needs you to be much more specific than “home.”

While the whole “Can a time traveler choose where they travel to?” question remains frustratingly unclarified, there is a one-time travel rule that seems pretty hard and fast on Outlander.

As showrunner and executive producer Ron Moore once explained to IGN, “The fundamental concept that Diana [Gabaldon] established is that when Claire goes into the past and spends two years there when she returns to the 20th century, two years have also passed.”

This rule—the idea that time passes at the same interval on both sides of the stone—becomes extremely important in Season 3, when Claire decides she wants to travel back to Jamie.

Moore goes on to say, “So in the 1968 story, […] when they start thinking about sending her back again, they realize that twenty years have also passed for Jamie in the past. One of the conceits of this show is when you’re traveling through and spending time, that much time elapses on the other side.”

Before Claire went back to Craigh na Dun, they spent time trying to confirm that Jamie was still alive and well 20 years later in his time. That much makes sense unless you think too hard about how it could possibly be true if a time traveler can be pulled to a specific time by a person but you know, it’s best not to overthink it lest your brain melts or something. Perhaps all of the time travel rules will become much clearer as, well, time goes on.

Why does a person time travel on Outlander?

To find a love that transcends space and time, duh.