Written by Kelley, The Big Sky is based on The Highway, the first book in C.J. Box's Cassie Dewell series of novels. In the procedural thriller, private detective Cassie Dewell partners with ex-cop Jenny Hoyt (Winnick) on a search for two sisters who have been kidnapped by a truck driver on a remote highway in Montana. When they discover that these are not the only girls who have disappeared in the area, they must race against the clock to stop the killer before another woman is taken.
Winnick is best known for her starring role as Lagertha in Vikings, which is halfway through airing its sixth and final season on History. She made her directorial debut in Season 6. Winnick can next be seen in Sean Penn's Flag Day where she stars alongside Penn, Josh Brolin and Miles Teller; in Wander opposite Tommy Lee Jones and Aaron Eckhart; and in Minuteman opposite Liam Neeson. She is repped by CAA, Alchemy Entertainment and Jackoway Austen Tyerman.