Nuclear radiation provides the unusual backdrop for a love affair in Grand Central. Tahar Rahim plays Gary, a man with an unclear criminal background who begins work at a nuclear power plant, where several employees take him under their wing and advise how to stay safe and get ahead. One night after work, he meets Karole (Seydoux), the fiancée of co-worker Toni (Denis Ménochet). Following an immediate attraction, the two promptly fail to keep their passions and loyalties in check and begin romping on a regular basis.
The details of the unique setting of Grand Central prove interesting, but the film itself is dramatically inert in execution. The "for the hell of it" nature of the romance befits Gary's reckless approach to the dangers of his workplace, but the sketchy characterisation throughout doesn't make that topic all that compelling. Seydoux, in particular, is saddled with an arbitrary, enigmatic vixen role in an ultimately too slight drama where ambiguities aren't really a virtue.