Episode 2

S1 E2: Colin's hand is forced when Lesley threatens to leave him, and with Hazel's help he immediately puts his plan to murder Lesley and Trevor into motion. He pipes carbon monoxide fumes into their bedrooms while they sleep, and then stages their deaths as a double suicide in Lesley's father's garage. The following morning Colin and Hazel feign their shock at the deaths speculating that Lesley and Trevor must have been driven to suicide by the anguish caused by their affair. But the police sense that something is not quite right.