Karen, a recovering addict, has settled into a successful new life with her husband and young daughter. When Karl, an old boyfriend recently released from prison, turns up unexpectedly, Karen's buried past comes back to haunt her. Karen is forced to go on a road trip and confront a world she thought she'd escaped from if she is to protect her family and her future.

Inspired by an ancient myth, Darklight stars Shiri Appleby as the immortal Lilith, long hunted by a secret society known as the Faith. Her true nature concealed by a powerful spell, Lilith lives as a 24-year-old woman with no memory of her ageless past. Now, the Faith's chief agent, William Shaw, must recruit Lilith and train her to use her mystical power, known as Darklight, for the good of humanity. So begins Lilith's heroic journey; to slay a deadly demon and come to terms with her own dark past.