1913, shortly before the outbreak of WWI. A group of aristocrats gathers at the estate of Sir Randolph Nettleby for a weekend shoot. As the terminal decrepitude of a dying class is reflected in the social interactions and hypocrisy of its members, only world weary Sir Randolph seems to realise that the sun is setting.

Two strangers, both married to others, meet in a railway station and soon find themselves in a brief but intense affair.

Routine tests on a traffic accident victim lead to shocking discoveries when the man's blood is found to be unidentifiable and x-rays reveal a disc embedded in his brain. His fabulous tale of being an escaped prisoner from an alien spaceship takes a turn for the sinister when the hospital staff realise that they're under a state of siege...