Mercy Brennan followed in her father's footsteps in a law enforcement career, but she has no interest in any other connection to him. A US Marshal in St. Louis, Missouri, she's assigned to a joint task force with the St. Louis PD that puts her back into contact with her father and in the sights of St. Louis's most powerful gang.
When the gang has reason to believe Mercy has possession of some highly sensitive and incriminating information, her boss assigns Mark St. Laurent - a Deputy US Marshal and Mercy's ex-boyfriend - to get her out of town until they can guarantee her safety.
Initially unaware of the danger she's in and uncomfortable working with Mark, Mercy's frustration escalates when she discovers the extent her boss and Mark have been keeping her in the dark. It isn't until a freak ice storm hits, stranding them at a remote location and out of contact with the district office, that the full severity of their situation becomes clear. As the storm worsens, the forces of nature combine with a deadly enemy closing in to put their lives at imminent risk. Can they survive long enough for help to arrive - if help is even coming at all?