As a newspaper reporter in San Antonio, Martin Gallagher's life has been predictable and mundane. But his routine existence suddenly explodes when his half sister Stella reveals that she is the secret leader of a Mexican revolutionary movement, and she desperately needs his help. Stella begs Martin to take a briefcase of secret documents to a certain destination in Mexico. Martin's loyalty to his sister overrides his better judgment: he agrees to make the delivery.

Plunged into a maelstrom of revolutionary conspiracies, Martin is soon on the run, scrambling across the border as he tries to out-maneuver competing intelligence agencies and shadowy figures who seem to have no loyalties at all. Just when he thinks he is safe, Martin discovers he is being stalked by a brutal and clever assassin known as Tony Sleep. Martin knows he won't be able to survive alone. Unfortunately, Stella may be the only one he can turn to–and she's in no position to help.