Barney Ross leads a band of highly skilled mercenaries including knife enthusiast Lee Christmas, a martial arts expert Yin Yang, heavy weapons specialist Hale Caesar, demolitionist Toll Road, and a loose-cannon sniper Gunner Jensen. When the group is commissioned by the mysterious Mr. Church to assassinate the dictator of a small South American island, Barney and Lee visit the remote locale to scout out their opposition and discover the true nature of the conflict engulfing the city.

Katherine Morrissey, a former Christian missionary, lost her faith after the tragic deaths of her family. Now she applies her expertise to debunking religious phenomena. When a series of biblical plagues overrun a small town, Katherine arrives to prove that a supernatural force is not behind the occurrences, but soon finds that science cannot explain what is happening. Instead, she must regain her faith to combat the evil that waits in a Louisiana swamp.