In order to save Paris from an international bloodbath, a grieving scientist is forced to face her tragic past when a giant shark appears in the Seine.
Three students celebrate their graduation with a visit of the Paris catacombs. When they discover a bunker, little do they know it's not the only thing that Nazi have left behind...
A mother, herself retired from the police, embarks on an underground exploration of Paris to find her daughter, a missing investigator on a mission.