A serial killer is targeting courting couples.

As a smog envelops London, bringing the city to a standstill, a serial killer begins targeting courting couples. The press suspects it to be the work of "The Butcher,"believed to be responsible for a series of unsolved murders from the 1930s. Jericho traces the murders back to a cinema where the couples had seen the same film prior to their deaths. Deadly secrets reveal themselves as Jericho's team investigates further.