In a staid English seaside town after the Second World War, young Lynda grows up with her widowed father and younger sister. Rebellious Lynda has been swearing constantly from an early age. At sixteen, she becomes more exhibitionist and seeks out sexual encounters challenging the prevailing lower-middle class attitudes to sex. She eventually becomes pregnant by an acquaintance of her father.
The final segment of the Key to Time is at the heart of a devastating war between neighbouring planets Atrios and Zeos. The Fourth Doctor discovers that a sinister entity is manipulating events and the cost of obtaining the final segment may be more personal than he imagined.
When one of Regan's snouts complains that his girlfriend's recent suicide was murder, the flying squad detective feels compelled to investigate. He uncovers a conspiracy that reaches the heart of the government, and finds himself fitted up, suspended and under the scrutiny of Special Branch.
