Kaye's world is shaken up when her sister Ruby returns with her boyfriend Michael. Eleswhere, as night falls, the Donahue family prepare nervously for the formidable race ahead.

The race is on and the road ahead is packed with dangers. The Donahues face up to a huge setback. Then, things go wrong on the Thames.

London's huge wall presents the racers with another massive obstacle, while the General and Faith hatch a sneaky plan and Jenny grows increasingly anxious.

London's huge wall presents the racers with another massive obstacle. Meanwhile, The General and Faith hatch a sneaky plan and Jenny grows increasingly anxious.

Lou and Hanmei crash into each other while vying for position on a country lane, forcing them to venture to a nearby farm to search for spare parts.

The ambulance, the hot hatch and the Volvo all chase an impenetrable Brookeheath prison truck containing some important cargo, heading towards the badlands of Manchester.

The remaining racers near the finish line as they approach the Highlands, and Kaye reveals a secret she has been keeping for years when she makes a shocking confession to Michael.

An act of sabotage causes all hell to break loose. From the chaos, the final contenders emerge. Season finale.