Eight years after the debut of its last sci-fi show, miniseries-turned-series 4400, USA Network is re-entering the genre space with Horizon, a cast-contingent drama pilot from The Walking Dead executive producer Gale Anne Hurd.

Set during the height of World War II, Horizon centers on a secretary at the FBI who discovers that her husband might have been killed in a battle with a spaceship in the South Pacific. Obsessed with learning the truth, she becomes the only person standing between Earth and an alien invasion. Bridget Tyler (Burn Notice) wrote the script and will co-executive produce for Universal Cable Prods. and Hurd’s Valhalla Entertainment, which has a deal at the studio. “Horizon is our first genre piece since The 4400 and the first ever period drama for the network,” said USA Network co-presidents Jeff Wachtel and Chris McCumber. “This signals the next step in the evolution of our programming brand.”

USA’s EVP Bill McGoldrick said the network’s brass “had been actively thinking about how to do genre and period dramas and what an USA genre and period show is” when SVP Alex Sepiol came across Tyler’s script submitted as a writing sample for a staffing job. Everyone loved the script, which combined period and genre drama. “We’ve killed two birds with one stone,” McGoldrick quipped. The number of birds quickly went up to three after Hurd was brought in as executive producer. The producer signed a pod deal with sibling studio Universal Cable Prods. in April, and USA brass had been looking for ways to work with her. Horizon was in the same batch of scripts with the one by Numbers creators Nicolas Falacci & Cheryl Heuton, which received a pilot order in September. The pickup of Horizon took longer as the network took time to figure out the logistics of doing period and genre drama.

With Horizon, USA extends its track record of betting on relatively unknown writers by giving them their first shot at creating their own series. Sepiol previously brought in Burn Notice by Matt Nix, While Collar by Jeff Eastin and Suits by Aaron Korsh to USA and oversaw the development of USA’s new series from Eastin, Graceland.

This marks the latest step in a rapid portfolio expansion for USA which, over the past two years, has added unscripted and comedy programming into the mix. On the reality front, the network is set to debut three new series in 2013 — The Moment, The Choir and Partners In Crime and recently started production on the pilot Bride Or Best Man, ordered a pilot for All In and moved The Cowboy Way into development (all working titles). In comedy, USA is on track to debut its first comedy series with the launch of its off-network acquisition Modern Family next September with two pilots vying for a spot, Sirens and Paging Dr. Freed.