Aboard his luxury yacht in the harbour of Monaco, a British agent in possession of secret papers is brutally gunned down. The papers are stolen and the yacht is mined, taking it to the bottom. While the British Security Service quickly determines that this was murder and not an accident, they are unable to progress the investigation. The leader of the investigation calls in an old friend — Lady Penelope Creighton-Ward.
While Lady Penelope quickly identifies those responsible, she's hampered in her investigation after they tie her to a chair and place a timed explosive by her feet. The explosion should draw off the investigators and allow the criminals to escape in their submarine. Unfortunately for them, the crooks hadn't counted on the fact that everything Lady Penelope owns has a radio in it, and International Rescue arrive rapidly to save their friend. Thunderbird 1 brings Scott to save Lady Penelope from the bomb, while Thunderbird 4 pumps the submarine full of knockout gas.
- Affectionate Parody: Of the James Bond franchise, complete with the spy-theme music.
- Expy: Of James Bond... with the inventive name of Jimmy Bondson. He even looks a bit like Sean Connery.
- Hand Signals: To warn International Rescue without letting the enemy agent that is with her know who she is, Lady Penelope uses a special form of signal language that to an outside observer looks like she is just putting on make-up.
- MacGuffin: The stolen papers.
- Humiliating Wager: Parker has a hard time confessing to Lady Penelope he accidentally gambled away her yacht in the Casino.
- Shoe Phone: Lady Penelope's powder-compact communicator.
- Spy Fiction: Way further up the Martini end of the scale this time.
- Stiff Upper Lip: Lady Penelope remains calm and unimpressed, even when she is shot at, taken captive and eventually tied up and left behind with a bomb. The enemy agent that abducted her even lampshades it.
- We Need a Distraction: The spies that stole the papers plan to blow up a boathouse (with Lady Penelope inside) to distract a police boat so that their submarine, which is on the bottom of the harbor, can leave unnoticed.