At the Saint Ignatius Orphanage, a rebellious boy named John Rossi refers to himself as "Simon Templar" and leads a group of fellow orphans as they attempt to run away to escape their harsh treatment. When Simon is caught by the head priest, he witnesses the tragic death of a girl he had taken a liking to when she accidentally falls from a balcony.
As an adult, Simon (Val Kilmer) now a professional thief dubbed "The Saint" for using the names of Catholic saints as aliases steals a valuable microchip belonging to a Russian oil company. Simon stages the burglary during a political rally held for the company's owner, Ivan Tretiak (Rade  erbed ija). Tretiak is a former Communist party boss and a billionaire oil and gas oligarch that is rallying support against the Russian President. Simon is caught in the act by Tretiak's son Ilya (Valery Nikolaev) but escapes with the microchip. After learning of the heist, Tretiak contacts Simon and hires him to steal a revolutionary cold fusion formula discovered by American electrochemist Emma Russell (Elisabeth Shue). He wishes to acquire Emma's formula which creates clean, inexpensive energy so he can monopolize the energy market during a severe oil shortage in Russia.
Using the alias "Thomas More," Simon poses as an Afrikaner and steals the formula after having a one night stand with Emma. Tretiak learns Emma's formula is incomplete and orders his henchmen, led by his son Ilya, to kill Simon and kidnap Emma in order to obtain the remaining information. Heartbroken, Emma reports the theft to Inspector Teal (Alun Armstrong) and Inspector Rabineau (Charlotte Cornwell) of Scotland Yard, who inform her Simon is a wanted international thief. Emma tracks down Simon to a hotel in Moscow and confronts him about the theft and his betrayal. The Russian police, loyal to Tretiak, arrest Simon and Emma. However, they manage to escape from the police van as they are being brought to Tretiak's mansion.
As they flee through the suburbs, Simon and Emma are helped by a prostitute and her family who shelter them in a hidden room in their home. Later, they meet "Frankie" (Irina Apeksimova), a fence who sells them the directions through an underground sewer system that lead to the American embassy. Simon and Emma exit the sewer tunnel only to find Ilya and his men waiting for them among a gathering of protestors outside the embassy's front gates. Emma safely makes it to the embassy for political asylum, while Simon allows himself to be caught by Ilya as a distraction. He escapes after rigging a car bomb that severely burns Ilya.
Simon plants a listening device in Tretiak's office and learns he plans to perform a coup d' tat by selling the cold fusion formula to Russian President Karpov to frame him for wasting billions on useless technology. Tretiak then plans to use the political fallout to install himself as President. Emma finishes the equations to complete the formula, and Simon delivers the information to Tretiak's physicist, Dr. Lev Botkin (Henry Goodman), who builds an apparatus which proves the formula works. Simon infiltrates the President's Kremlin residence and informs him of Tretiak's conspiracy just before Tretiak loyalists detain him. In front of a massive gathering in Red Square, Tretiak makes public accusations against President Karpov, but when the cold fusion reactor is successfully initiated, Tretiak is exposed as a fraud and arrested. He is also revealed to have caused the heating oil shortage in Moscow by illegally stockpiling vast amounts of heating oil underneath his mansion.
Sometime later, at a news conference at the University of Oxford, Emma presents her cold fusion formula to the world. Simon attends the conference in disguise and once again avoids being captured by Inspectors Teal and Rabineau when they spot him in the crowd. As he drives away, he listens to a news radio broadcast (voiced by Roger Moore) reporting that $3 billion was recently donated to the Red Cross, Salvation Army and the United Nations Children's Fund. It is implied that Simon, who had access to Tretiak's accounts, donated the money anonymously. Furthermore, a non-profit foundation led by Dr. Botkin is being established to develop the cold fusion technology.
Output: Where does Simon evade the Scotland Yard inspectors one final time?