Four teams of celebrities get behind the wheel of classic cars to compete in the Endurance Rally Association's Road to Saigon event, beginning in Northern Thailand and travelling 3000km through Cambodia and Vietnam. The teams consist of Noel Edmonds and his wife Liz in a MGB GT, married couple Martin and Shirlie Kemp in a 1972 Mini, mother and daughter Andi and Miquita Oliver in a 1959 Morris Minor, and friends Tinchy Stryder and Jordan Stephens in a Hillman Imp.
The teams face a race for the Cambodian border, despite two of the cars having been put out of action during the first leg of the journey. Noel and Liz and Andi and Miquita must drive through the night on treacherous roads if they are to reach the checkpoint before time runs out. Once over the border, the rally heads for Angkor Wat, the mysterious centrepiece of the ancient Khmer empire, which some believe could be evidence of an other-worldly civilisation. Finally, all four teams are reunited as they make their way to Phnom Penh.
The teams begins a 900 kilometre journey across Cambodia that takes three days to complete. Along the way, they drop in a market where insects and spiders can be bought as snacks and visit sites linked to the atrocities of the Khmer Rouge regime, including the S21 prison and the notorious Killing Fields. Fatigue and ill health starts to take its toll as they cross the border into Vietnam.
The teams have the finishing line in their sights as they travel along Vietnam's coastline to the closing ceremony in Saigon. Noel and Liz fear they may have pushed their car too far over the past 2,500 kilometres, Andi struggles to cope with long hours behind the wheel, and Tinchy and Jordan switch to driving a Soviet era jeep. The last day of the journey brings one duo to the brink of disaster. Last in the series.
