History
Captain Blacker stored several documents aboard the yacht, including a report regarding the Daleks (TV: The Man from MI.5) and their attempted invasion of Solturis (COMIC: The Penta Ray Factor) as well as Hans Werger's testimony about the "fierce gun battle" in Germany (TV: The Man from MI.5) caused by Mr Steelman, (COMIC: The Return of Mr. Steelman) indicating some knowledge of these top secret events.
In an account dated to January 1965, Blacker had come into the possession of the plans to a nuclear device after being given them by a scientist. He stored these within the yacht, disguised as a battery within a torch. He planned to rendezvous with his fellow MI5 agents Jimmy Bondson and Tidman as cover for him passing the plans over to Bondson. Before they could reach him, however, criminal gang leader Carl snuck aboard the ship and shot Blacker 5 times with a Henrietta .45 Supermatic, before rifling through his possessions and ultimately finding the plans, stealing them, and blowing up the ship.
This explosion occurred within the view of Bondson and Tidman, who were just arriving in their own ship. Bondson decided to don diving gear to search the wreck for the plans, and found Blacker's corpse, and no sign of the plans, with the torch case empty. As a result, he decided to contact International Rescue for help, leading London agent Lady Penelope Creighton-Ward to contact him, albeit anonymously.
After agreeing to meet up there, Bondson explained the situation to her in the Forest of Digne, divulging some details regarding the yacht, their plans to pass the plans over, as well as the plans themselves, although he couldn't disclose everything about the latter for security reasons. Ultimately, International Rescue agreed to help, and were successful in recovering the plans and delivering them to Bondson. (TV: The Man from MI.5)
Other sources dated the activities of International Rescue to the 1990s, (PROSE: The Dying Days) the 2060s, (PROSE: Titan Declares War! et al.) and the 2080s. (PROSE: Captain Scarlet in Death Crash! et al.)