The first part of a four-part drama. Mysterious financial losses lead the Post Office to sack and prosecute village sub-postmasters who have no way to prove their innocence.

Alan Bates and the sub-postmasters begin their fightback with new allies in Westminster, but first they must convince an independent investigator of their honesty.

Alan allies with the Post Office in the hope his friends can get justice at last, but can he trust the people who have let them down so badly?