In the medieval period, a 10-year-old prince named Freddie, voiced by Ben Kingsley, becomes an orphan after his evil aunt, Messina, murders his parents in a bid to claim the throne for herself. Instead of killing the young prince outright, Messina transforms him into a frog, which sets the stage for his extraordinary early life. Escaping her clutches, Freddie spends his childhood living as a frog, adapting to his new form and environment, and he becomes known as Freddie the Frog. The story then shifts to the 20th century, where Freddie, now grown, seemingly has achieved near-immortality and becomes a secret agent with the code name F.R.O.7, working for the French Secret Service.
One day, he is summoned to London by the British Secret Service, where a villainous character known as El Supremo, voiced by Brian Blessed, is carrying out a bizarre scheme—stealing the UK's most iconic landmarks such as Nelson's Column, the Tower of London, Buckingham Palace, St. Paul's Cathedral, and Stonehenge. By the time Freddie arrives in London, several of these monuments have already vanished, leading to a sense of urgency. Assisting Freddie in his mission is his active team: Brigadier G, voiced by Nigel Hawthorne, a seasoned military figure; Daffers (short for Daphne Fortescue), a martial arts expert; Scotty, a skilled weapons specialist; and Trilby, who is later revealed to be a spy for the villains. Interestingly, Freddie learns that El Supremo's next target is Big Ben.
The plot intensifies when the team uncovers El Supremo's plan to utilize a secret island in the Outer Hebrides, where he aims to use tiny versions of famous landmarks as batteries to power a massive crystal. The crystal is destined to send out a sleeping virus that would paralyze the entire planet, giving El Supremo control over the world. During their investigation, Freddie and Scotty are thrown into a pool filled with sea monsters, while Daffers is captured and brainwashed into becoming a subordinate of El Supremo and Messina.
El Supremo begins unleashing his virus across Great Britain, causing the entire country to shut down as people fall into deep sleep. The stakes escalate as Freddie teams up with his old friend, the Loch Ness Monster, to rescue Daffers from the snake guards disguised as other creatures and to thwart the villain’s plans. A tense and action-packed final battle unfolds where Freddie, Daffers, Scotty, and the Loch Ness Monster confront El Supremo and Messina’s forces. During the fight, Freddie and his friends manage to shrink El Supremo to an ant's size, preventing him from prevailing.
The climax reaches a peak when Messina, who is still alive and dangerous, attempts to attack by shapeshifting into various creatures—a bat, a hyena, a scorpion, and a boa constrictor—only to be ultimately electrocuted when Freddie throws her into an electrical pole. The intervention of Brigadier G and his team ensures the villains are defeated, and Trilby is revealed to be a traitor aiding the enemy. With order restored, Britain is back to normal, and Freddie, Daffers, and Scotty are celebrated as heroes.
However, peace is short-lived as they receive an urgent call from the United States—Messina, who survived her apparent demise, is secretly plotting to extend her reign of terror to Washington, D.C.. Furious and determined, Freddie and his team, alongside the Loch Ness Monster, gear up once again to face this new threat and prevent Messina from destabilizing another world power. The movie combines adventure, humor, and a touch of fantasy, emphasizing themes of heroism, loyalty, and resilience in the face of villainous plots.
