Samir Horn is a former soldier, a devout Moslem, and U.S. citizen in the Middle East selling bomb detonators to Islamic radicals. He joins their cause as both the FBI and a rogue CIA agent track him. Horn escapes a Yemeni prison, goes underground in France where he proves his abilities, and is sent to the United States to choreograph a simultaneous and multiple terror attack. Will the intelligence agencies talk to each other, and can Horn be stopped?

Fox Mulder and Dana Scully both worked at the FBI as partners, a bond between them that led to their becoming lovers. But now they're out of the FBI and have begun new careers. Scully works as a staff physician at a Catholic hospital. Her focus these days is on a young boy with an incurable brain disease. Administration wants to give up on him. Scully, who feels a special bond with the boy, does not. Meanwhile, Mulder's focus is on clipping newspaper articles, throwing pencils into his ceiling and writing about the paranormal. Scully and Mulder are brought together as partners again when a special case requires Mulder's expertise and Scully is prevailed upon to convince him to help. The case involves a pedophile priest who claims he is having psychic visions regarding the whereabouts of a missing FBI agent.

Andrey is the head of a group of Moscovites who live in the city's underground. Owen leads a rescue team in search of a Russian anthropologist who's disappeared beneath the underground system. They discover an eerie multilevel system of caves and catacombs.

The story deals with the characters Pistolero, the Gent and Comanche and the deadly, unfinished business among them.