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...

• Merton Park Studios
• Edward Judd
• Yoko Tani
• Valerie Gearon
• Lyndon Brook
• Ric Young
• Tsai Chin
• Barrie Ingham
• Anthony Sharp