Set in the present-day, DNA portrays a Britain occupied by victorious German forces back in 1941. John McCarthy, an ageing journalist working for Der Alemanne, goes looking for his missing drinking buddy, Jimmy. With no one to help, he unwittingly seeks out an old girlfriend, Bernadine Clarke, now a Chief Inspector at the Met. She at first appears willing to help but things are not all that they seem. Undeterred by his apparent lack of progress, John persists in his search only to stumble upon the awful truth behind recent police roundups.