Three-part ITV drama about real-life killer Malcolm Webster & the crimes he committed in the 1990s When his wife Claire (Sheridan Smith) becomes suspicious about unpaid bills & credit card debts Webster (Reece Shearsmith) at the time working as a nurse poisons her & deliberately crashes their car setting it on fire & leaving her inside Three years later he marries Felicity Drumm (Kate Fleetwood) in New Zealand & soon after begins plotting her murder in order to receive money from forged life insurance policies His plan fails however & with Felicity now aware of Webster&s true nature he leaves the country & moves onto a potential third victim Simone Banarjee (Archie Panjabi) Will investigating Detective Inspector Charlie Henry (John Hannah) catch Webster before it&s too late?