The Passage” star Saniyya Sidney was unaware that the book version of her character was originally white until her father, a fan of Justin Cronin’s apocalyptic trilogy, informed her during the audition process.

“I was like, ‘Oh, she is?'” Sidney told Variety at Thursday’s series premiere in Santa Monica, Calif. “And when I got it, I was like, ‘Oh, this is going to be different.'”

But Sidney paid no mind to the change when approaching the role of Amy Bellafonte, a 10-year-old orphan who finds herself at the center of an apocalyptic science experiment in a world plagued by vampires and a deadly virus.

“To be able to be an African-American girl that was originally white in the books, I’m honored, but I believe it’s no different,” Sidney said. “As long as you connect with how she is and just connect with Amy was important, and that’s what I put first before anything.”

Amy is also four years older than her novelistic counterpart, an alteration Fox entertainment president Michael Thorn said was necessary to capture the emotional depth of the youthful, but “sophisticated” role.

“The age is funny because our actress is getting older and older every single day,” Thorn said. “We needed an actress who could play that part and carry the weight of saving humanity in a way where she could be childlike but grow into this heroine, and so for us, it wasn’t about the most specific age. It was about, who’s this actress who could carry it?”

Sidney succeeded in carrying a sense of maturity both on and offscreen, according to co-star Mark-Paul Gosselaar. His character, Brad Wolgast, spends much of the series fighting to protect Amy from her government pursuers.

“You’re told never to work with animals or children, for obvious reasons,” Gosselaar joked. “This was an exception that pleasantly produced an unbelievable result. She is brilliant. I started the business roughly about the same age as she did, and I had nowhere near the wisdom or the wherewithal that she possesses, so it was a pleasure to be her partner.”

Like Sidney, Gosselaar got his big break at a young age on the hit ’90’s sitcom, “Saved by the Bell,” a similarity that both connected him with and divided him from his young co-star — too young to be aware of once-teenage-dreamboat Zack Morris.

“The only Zac I knew was Zac Efron, okay?” Sidney teased Gosselaar on the carpet.

Another major diversion from the source material included Brianne Howey‘s character, Shauna Babcock, a test-subject-turned-vampire who is male in Cronin’s books. Like Sidney, Howey was grateful for the switch.

“I think it’s incredible,” she said of the changes. “I couldn’t be happier to get to be a part of it.”

Aside from the novel-to-screen differences, Emmanuelle Chriqui, who plays Brad’s ex-wife, Dr. Lila Kyle, admires both the books and the show for diverging from the action-first, humanity-later nature she notices in other genre series.

“For a genre show, it’s not often that you’re also dealing with love and relationships,” Chriqui said. “They really touch on the intimate moments. That is unique for a vampire show.”

Series that favor new, compelling stories and characters are the kind of content Thorn hopes to bring to all of Fox’s scripted programming when molding a branch of Fox that will escape the upcoming Fox-Disney merger.

“We’re still going to be a writer-driven company, where we look for really talented creators who have a voice, who have something to say, and whose series will hopefully be culture-piercing and still broadly appealing because we’re still a broadcast network,” Thorn said. “I hope that’s what ‘The Passage’ is. That’s what we think it is.”

“The Passage” premieres on Fox on Jan. 14.