Retired operative Mark Trent is presently teaching his craft to potential recruits. When his sister is murdered at a resort in Mexico he questions whether or not an old enemy from his past has returned. To solve her death Mark must return to his former career and join forces with both old and new colleagues who all operate in the world of secret operations. Based in Washington D.C., and hidden under the umbrella of a high-tech business, members of the Nimbus Services team will be forced to confront a maniacal madman who plans to inhabit a world of his own making.