What would life be like if we all knew the exact day we would die?

In The Raging Ones, Krista and Becca Ritchie imagine a world where your deathday dictates your fate: Those who will live at least 30 years are Influentials, who are educated and work in skilled careers like medicine and engineering; those with 13 to 29 years to live are Fast-Trackers, who live wildly and work hard at unskilled and dangerous jobs; and finally those with fewer than 12 years of life are Babes, who live only to be loved by their families.

Influential society is similar to ours, but Fast-Trackers are much less concerned with social niceties—for better and worse. “If you really do not have a certain amount of time to live what would be almost like a frivolous part of your life? Caring about certain things like nudity and these bras and all of that seems like frivolous when you just want to get to the basic passion of life,” Becca points out.

When 17-year-old Franny Bluecastle survives the day she was scheduled to die, she finds herself psychically linked to two other teens who dodged their death days, Mykal Kickfall and Court Icecastle. The three must work together to make it onto the planet’s one space craft, where they’ll be able to escape the dire fate that awaits them if anyone finds out they’ve lived past their deathdays.

Although they relate to the three characters’ profound love for each other, Krista and Becca don’t share their mental link. “We definitely don’t have a psychic bond,” Krista says. “We’re always jealous of the twins who say they have psychic bonds,” Becca adds, “I’m like, How?”

Despite their unfortunate lack of psychic abilities, the twins work together remarkably well. “We’re definitely like two sides of a coin as writers,” Krista says. “It’s like I’m the brain and she’s the heart.” She likens their writing process to building a human body. After they decide on a story idea, Krista writes a rough 30,000-word draft of the story, what she calls the skeleton. Becca writes behind her, adding detail and building the characterization that constitutes the book’s organs. Each takes a second pass, filling in the final touches.

They’ve developed this process over years of writing together. They grew up watching movies with their family and fell in love with telling stories and developing characters. Becca started writing her own stories at 12 and Krista followed her lead not much later. By college they were collaborating on novels together. “We realized that we complemented each other really well,” Krista says. “I’m very analytical; she’s more imaginative and creative.”

Though their previous published novels are all contemporary romance, YA fantasy and science fiction was their first passion. “Science fiction has always been really interesting,” Krista says, “because it takes one element from our world and changes it and then extrapolates on how everything would be different.” It was exciting for the Ritchies to return to that kind of world building and to incorporate the character-building skills they developed writing romance.

They’re now working on the sequel to The Raging Ones and enjoying the challenge of answering the many questions they raised in the first book. “I’m so excited for people to read that one now,” Becca says, “and this one’s not even out!”

Alex Heimbach is a writer and editor in California.