When Carmen Ejogo signed on for HBO’s True Detective Season 3, she didn’t know exactly what she was getting into.

“I was only given three episodes by [show writer] Nic Pizzolatto,” Ejogo said about considering the role. Those first episodes show flashes of True Detective‘s schoolteacher-turned-true crime author Amelia Reardon, and tease her relationship with Wayne (Mahershala Ali). But as Ejogo noted to Decider when we spoke to the actress over the phone, they don’t establish her as a fully formed character.

“The first three episodes were not that useful to me, and so in a way I was a little hesitant to take the job on because she hadn’t been fully described to me yet,” Ejogo said. “What was on the page was really just a woman who had ambitions but who, certainly in the first three episodes, hadn’t realized them [and] was arguing a lot with her husband. I felt like I’ve seen this before.”

Five episodes into the season, viewers now have more of a sense of how central Reardon is to the show’s central mystery: what happened to the Purcell children? And Ejogo’s hesitance started to dissolve once show creator Nic Pizzolatto further explained how crucial the role really is. When she learned that Amelia would come to be the pivotal turning point connecting the show’s three timelines and their central kidnapping plot, Ejogo decided to take a leap of faith.

“I could just tell that Nic has the acumen and the capacity to pull off what he was describing, which is very epic, quite poetic, and Amelia really is at the core of that intention and that ambition,” Ejogo said.

According to the actress, though she didn’t see scripts until months into filming, Pizzolatto described her as someone who had been to the West Coast, had been part of the Black Panther movement, and had experienced a lot of group sex. After learning that the world wasn’t everything she hoped, Amelia returned to Arkansas a bit more cynical and a bit more inclined to be jaded.

“I’m personally not interested in playing women that aren’t highly multi-dimensional and nuanced and as dynamic as the men on the page. So I wouldn’t be part of the show if I didn’t think that’s what I was getting in to,” Ejogo noted. “And you know, I also recognize that Nick was willing and smart enough to allow input in places that would take it even further.

“In the end, what you see on the screen, I hope, is what Nic had always hoped for. Which was in Amelia certainly a very complex, pivotal, and dynamic character.”

In addition to slowly piecing together who her character was, Ejogo also had to balance the intensity of acting against Mahershala Ali’s very different acting style and the confusion of Season 3’s alternating timelines. “[Mahershala and I] sort of embodied two personalities who maybe should have never met, which is an interesting thing to have to play and work through because they really don’t get each other in a lot of ways. And yet they are absolutely designed for each other in the end,” Ejogo said.

As for this season’s multiple timelines, they’re as ambitious to create as they are to watch. True Detective Season 3 follows the same crime and characters over three periods in history: the 1980s when the Purcell kidnapping first happened; 10 years later in the 1990s when the case was reopened; and 15 years later when a documentary is being filmed about the case. Most of Ejogo’s scenes portray Amelia either as the sweet new love interest in the ’80s or the hardened yet excited wife and author in the ’90s. At times, the actress was asked to quickly jump between these two mindsets.

“It’s not like some shows or movies where you can sort of, you can discover things as you go. I feel like on this job I had to be as clear-minded as what I was trying to aim for from the very start. So on a day when you are doing three different timelines on a single day of shooting, you really know where you’re at at any given moment,” Ejogo recalled. “I tried to be as off page with all of that material upfront, which is a hell of a lot of material to take on.”

Ejogo credits True Detective’s period appropriate costume department for helping her transition into who Amelia needed to be. But this isn’t the first time the actress has worked with multiple timelines. Ejogo has played author and the wife of Martin Luther King Jr. Coretta Scott King twice, in two different projects. In the 2001 TV movie Boycott Ejogo played the activist during the 1950s bus boycott, and in Selma her portrayal was linked to the Civil Rights Act of 1964. This experience helped her adapt to Amelia’s timeline-changing mindset.

“There were definitely days that I was having to switch out in those time periods for sure. It kinda feel spiritual, you know? Having to quickly change backstage and come out and re-emerge as somebody else. I kind of strangely enjoyed it,” Ejogo explained.

As Episode 5 has teased, Amelia isn’t merely destined to be the supportive but emotionally complicated wife in Wayne’s story. “If You Have Ghosts” ends with the oldest version of Wayne finally cracking open his wife’s book on the Purcell case. That’s when he learns that the Purcell children’s mother Lucy (Mamie Gummer) said the phrase “Children should laugh” — something that appeared word for word in the case’s original ransom note. According to Ejogo, it’s not that there is a massive secret hiding behind this marriage. It’s that Wayne’s feelings of emasculation prevented him from opening what may become one of his most valuable resources, her book.

“It’s not so much that Amelia’s been hiding stuff. It’s just that Wayne hasn’t wanted to look for stuff, hasn’t wanted to see things,” Ejogo said.

Now that he’s finally seeing them, and seeing his wife, this series is going to permanently change.

New episodes of True Detective premiere on HBO Sundays at 9/8c.

Watch True Detective on HBO Go and HBO NOW