In this series the priest finds himself embroiled with the Secret Service, which puts Lady Felicia in a compromising position. Sid is sent undercover into a theological college to flush out a killer and Mrs McCarthy takes on a group of travellers when a local man is found dead. Finally a fugitive takes sanctuary in St Mary's. Father Brown is stunned to realise that the man in the confessional is in fact Inspector Sullivan - and he's wanted for murder.