A 62-page self-published space opera seems an unlikely candidate for the New York Times bestseller list. Yet in July 2016, part one of Zenith, the first installment of the Androma Saga by authors Lindsay Cummings and Sasha Alsberg, reached the #1 spot on the young adult e-book list in its first week of publication.

The serialization follows a mercenary named Androma who commands a glass starship with an all-female crew of space pirates—a classic entry in a science fiction subgenre that blends romance with space warfare and a bit of melodrama. (The space opera subgenre is perhaps best known for Orson Scott Card’s Ender’s Game and George Lucas’s Star Wars.) Soon traditional publishers took note and were bidding for the right to publish the full manuscript.

“My Twitter feed was on fire that week with people reading Zenith, raving about it, and congratulating Sasha and Lindsay on their New York Times hit,” says acquiring editor Lauren Smulski at Harlequin Teen. At auction, the company secured world English rights to the book and its sequel. “Sci-fi space opera is still very underrepresented in the young adult market,” Smulski says. She notes that the book stands out for its use of space tech (including the glass spaceship) and its building of the Mirabel Galaxy’s exotic and imaginative worlds—“from war-torn, poisonous Xen Pterra to the immensely colorful giant tree villages on Adhira.” The authors say the book also resonates with readers for its exploration of female friendships.

Cummings has released two YA series with the HarperCollins imprints Greenwillow Books (the Murder Complex series) and Katherine Tegen Books (the Balance Keepers series). Alsberg has more than 300,000 subscribers to her YouTube channel, ABookUtopia, where she posts book reviews and related news. Combined, the two have about half a million social media followers. Both authors also already had agents who acted as consultants for the initial e-book. Joanna Volpe at New Leaf Literary and Peter Knapp at Park Literary helped their clients with publicity and marketing ideas and cover design, and acted as beta readers.

Once the book hit the bestseller list, the group was in agreement that it should be sent out on submission to traditional publishers. “We decided we wanted to give readers the full book instead of continuing it in parts,” Cummings says.

The partnership began when Cummings reached out on Instagram to offer Alsberg an advanced reading copy of her book for review on her channel. “It developed into a friendship following that, because we were into the same types of books and fandoms,” Alsberg says. (Cummings is a fan of C.S. Lewis, Sarah J. Maas, J.K. Rowling, and Scott Westerfeld, and Alsberg cites Diana Gabaldon and Maria V. Snyder as her influences.) Last year, the pair began discussing writing something together as a side project.

At the time, Alsberg was working full time on her YouTube channel and Cummings was working on other writing projects, also full time. Together, they came up with what they describe as a “really strange” process. It is made more unusual by the fact that until recently the two lived in different states. “We use Google Docs, and write in live time, while also on Skype together,” explains Alsberg. “We plot the overall major points of the story, then fill in the blanks in between as we go.”

The two writers now both reside in the same northern Texas town—and they anticipate that their close proximity will allow them to get a lot more writing done. In fact, Cummings and Alsberg have already delivered the first draft of Zenith, expanding their 62-page bestseller into a full manuscript just six weeks after it was acquired by Harlequin Teen. Zenith, the first book in the planned Androma Saga duology, is scheduled for January 2018.

Jennifer McCartney is a freelance writer and editor, and the author of the novel Afloat.