Five years into his retirement, CIA veteran Peter Devereaux is pulled back into service to help retrieve a Russian agent -- also his former lover -- who has incriminating evidence on Federov, a corrupt Russian leader. When a different CIA team, led by Devereaux's former protege, shows up, the mission goes south and Devereaux's ex-lover is killed. Now a rogue agent, Devereaux drags a relief worker along on his mission to settle the score.
Archaeologist Scarlett Marlowe has devoted her whole life to finding one of history's greatest treasures: Flamel's Philosopher's Stone. According to legend, the artifact can grant eternal life and turn any metal into gold. When she learns that the stone is hidden underground in the Catacombs of Paris, she assembles a crew to guide and document her historic mission. As they begin their descent, the team-members have no way of knowing that they are entering their own personal hell.
For five men, the opportunity to share a penthouse in the city -- in which to carry on extramarital affairs -- is a dream come true, until the dead body of an unknown woman turns up. Realizing that her killer must be one of their group, the men are gripped by paranoia as each one suspects another. Friendships are tested, loyalties are questioned, and marriages crumble while fear and suspicion run rampant.