Minder on the Orient Express

Nikki South inherits the contents of a bank strongbox after her father Jack South dies in 1975. She discovers that the items inside form a clue to the number of a Swiss bank account containing her father's ill-gotten gains. The revelation sets her on a path to claim the money using the envelope as a key.

On her way to her birthday party, Nikki is ambushed by masked attackers who try to seize the envelope containing the clues. She is saved by Terry McCann, a temporary doorman at the club where the party is to be held. The incident kicks off the pursuit for the envelope.

To thank him, Nikki gives Terry two return tickets for the Orient Express to Venice. Terry, unaware of her real motive, plans to bring along Annie, his girlfriend who works at the club. This creates tension as motives begin to diverge between the pair.

Nikki plans to travel to Switzerland with her boyfriend Mark on the same train that will carry the envelope's clues. Their aim is to claim the funds, while several former associates of Jack South eye the windfall. The plan sets the stage for a tense pursuit across the rails.

Several former associates of Jack South join the chase, including a bent bank manager, a hitman, and the widow of a former associate. They are determined to grab the envelope and its clues. The pursuit intensifies as the train journey unfolds.

Arthur Daley, a reluctant witness, is trying to avoid a subpoena to testify against a gangster. He manipulates Terry's girlfriend into thinking Terry's family has arrived, causing their relationship to crack. He then persuades a wary Terry to let him accompany them, evading the subpoena.

As they travel toward Folkestone Nikki enlists Terry to safeguard the envelope. They discover Detective Sergeant Chisholm and Interpol agent LeBlanc are traveling on the same train to observe the different players. The presence of law enforcement raises the stakes for everyone aboard.

In night time France a free for all breaks out aboard the train. Chisholm joins in, defending the police in a chaotic clash. When the emergency cord is pulled and the train halts, the quartet disembarks together.

Arthur, Terry, and Nikki exit the train and are joined by Chisholm on the platform. The pursuit shifts between carriages and stations as the envelope remains a coveted prize. Interpol's presence adds a formal edge to the pursuit.

Nikki and Terry manage to crack the code to the bank account number using Arsenal's 1971 FA Cup shirt numbers. They believe the clue reveals the Swiss account for the windfall. A fight on a local French train results in the partial account number being lost, ending the pursuit of the fortune.

With the partial Swiss account number lost, there is no pot of gold to claim. The would-be windfall disappears, leaving Nikki, Terry and their pursuers to reassess their plan. The group begins to head back toward Fulham Broadway.

Having failed to secure the windfall, the protagonists finally return to Fulham Broadway. The envelope and its clues are no longer a source of wealth, and the immediate danger subsides. The adventure closes with the characters back where it began.