While Gethin's mother spent most of the Second World War cracking German codes at Bletchley Park, his father was a conscientious objector.
As he grew up, and his mother maintained her Government-imposed silence on what she had been doing, Gethin's father was voluble on his pacifism, and Gethin dreaded the question 'What did your father do in the War?' The answer 'Nothing' seemed shameful.
Now, with his mother's story out in print, he sets off to find out why his father took the stance he did, the roots of the tradition of conscientious objection in the Welsh valleys, and how the family felt about the decision and the shame it brought.