Eight talented candidates have reached the final stage of selection to join the ranks of a mysterious and powerful corporation. Entering a windowless room, an Invigilator gives them eighty minutes to answer one simple question. He outlines three rules they must obey or be disqualified: don't talk to him or the armed guard by the door, don't spoil their papers and don't leave the room. He starts the clock and leaves. The candidates turn over their question papers, only to find they're completely...