The border is a hostile place with searing heat and venomous serpents. Yet the deadliest predator targets the innocent.

A sniper strikes in the Valley of the Sun and Detective Nathan Parker soon finds a connection between the victims-each of them had a role in an organization founded to help undocumented migrants make the dangerous crossing. Parker discovers no one is exactly who they seem.

There's the devil you know and then there's the devil within-when the two collide, no one is safe.