The monthly superintendents' meetings never hold much excitement for DI Charlie Priest, but this time he is in for a surprise. DCS Colin Swainby is to resign, quietly and without fuss, because certain allegations have been made against him. Allegations involving a woman, and it's not his wife.
When MP Edward Gross finds himself similarly compromised, he also opts for a quiet exit, but his has a far more permanent outcome. Priest knows there must be a connection - he has to prove it before the body count starts escalating.