Lord Will Arlington-Spencer and his best friend, actor Tom Marks are actually a pair of confidence tricksters who have carried out various scams in the name of restoring the economy of England, including selling London's Tower Bridge several times over. During their escapades, they are hounded by Inspector Jarvis, a police officerdetermined to prove the pair are crooks. After one close call too many, Will asks Margaret Thatcher for assistance, and she takes away not only Jarvis' job, but also his pension. Feeling responsible, Will takes Jarvis on as his manservant, and over time he and Tom lose touch. Years later, the British Space Agency unveils a prototype highly secret roboticLunar Explorer. Fiona Arlington-Spencer, Will's niece and a publicist for the BSA is secretly working with Tom's son Travis, a computer hacker, and they plan to steal the Explorer and sell it to both the Chinese and Russians. Unfortulately because they lack the plan and resources to pull off this job, they approach Will for help. Will agrees and reaches out to Tom and the two reunite. However, Will reveals that although he is not a policeman anymore, he suspects Jarvis is still trying to prove Will and Tom are crooks. An initial plan is made to sell to the Chinese and take the money before they can see the Explorer, however the Chinese are wary of the British, and refuse to discuss a price until they see the Explorer in person. Realising there is no other way, the team plan to steal the Explorer from the BSA. Unfortunately, Travis is kidnapped by impatient Russian goons as 'encouragement' for the sale, but because they need his help, Will and Tom trade an unsuspecting Jarvis for Travis. They successfully infiltrate the BSA at night, break through the Agency's security and steal the plans only to find the Explorer shown during the unveiling is a large polystyrene block, part of a Stage illusion. It is revealed that whole project is a con: the vehicle exists only as a table-top model, due to budgetary constraints. To carry through the plan, they decide to construct the vehicle themselves, but before they do the Russians agree to release Jarvis because he was annoying them. Over lunch, Jarvis comes to Will and asks to be cut in, having had enough of being on the outside, and Will agrees. After acquiring an assortment of second-hand parts, and basing the entire vehicle on a motorised lawn mower, they soon create a full-sized Explorer. The Russians are convinced enough to hand over the money, which as part of the plan, Jarvis takes away before the deal is closed. The Russians leave but it is revealed that they have driven away with the polystyrene block. Will and Tom reveal they are changing the plan: they intend to now destroy the Explorer, which despite being a fake was built using the genuine plans, to prevent it falling into foreign hands. The Russians quickly discover they were duped, and try to make off with the Explorer, but Will, Tom and Travis are able to escape with the vehicle. During a chase, the vehicle falls apart and is finally sunk in a flooded quarry. The group manage to evade police and Russians, but Jarvis still has the money. It is revealed that whilst prisoner, Jarvis and his Russian captors made plans to take the money themselves. However Will had suspected this all along, and thanks to a careful trick Jarvis and the Russian grunts are caught and arrested by Inspector Covington, and Jarvis is imprisoned for masterminding the theft. The money is turned over to the Director of the Agency, revealed to be a friend of Will and was aware of the plan all along, who now plans to actually complete the project.
