1951 Brighton. With the excitement of the war over and the Nazis brought to justice Mirabelle Bevan ex-Secret Service moves to the seaside to put the past behind her. She takes a job as a secretary at a debt collection agency run by Big Ben McGuigan but when confronted by the case of Romana Laszlo a pregnant Hungarian refugee Mirabelle discovers that her specialist knowledge is vital. With enthusiastic assistance from the pretty insurance clerk down the corridor Vesta Churchill Mirabelle follows a mysterious trail of gold sovereigns betting scams and bodies to a dark corner of Austerity Britain where forces of evil remain.