Dom and Mel face one of their toughest challenges yet: dealing with a builder who may well offer the worst value for money in Britain. The problem is, no one knows where he is... Christophe and Debra Montoya-Timperley have lived in their three-bedroom semi for ten years. But as their sons, Joshua and Max became older, the family had outgrown the house. So in 2008, they embarked on what they hoped would be a life-changing building project. The couple agreed to the builder's quote of £69,000. But after they had handed over £26,300 of their hard-earned cash, twelve weeks into the job the build came to standstill and the builder vanished without a trace – before he had even dug the foundations! The Montoya-Timperleys won a County Court settlement of £32,000, but they have never been able to track down the builder to get their money back. So Dom has a particularly tricky manhunt on his hands.He has to use all his cunning to find the builder and lure him into a carefully laid trap. Meanwhile, Melinda and her team face a huge challenge. Normally she is tasked with rectifying the mess a builder has left behind, but building an extension from the ground up is a first.

• Melinda Messenger
• Dominic Littlewood