The Beginning was the first novel in the series of books staring Lady Christina and her double decker spaceship the 200, in the book the origins of the ship's time travelling abilities are explained.
At the beginning, Cristina is driving around in the 200 when designs for how to make it travel in time fall on her head. She immediately implements them and to test it travels back in time one day, during this flight the plans fall out of the doors and onto the past incarnation of her; a huge paradox.
Wanted by the police she packs her bags and makes a longer time jump, she arrives in the 1970's and discovers a crashed alien artifact about the size of a cup, deciding it would be a bad decision to examine it here she sets off to a small island to look at it more closely.
Upon opening it she finds that it is a transmat device and contained in its memory were several large insectoid creatures. After an air battle, she draws them back to England where they are shot down by UNIT.
Before they can ask her any questions she takes off again and implements the teleport device into the 200's systems.
The book ends with the teleport taking her to the heart of a rainforest where many tribesmen are wielding strange laser-like devices.