Ep 5. Avalanche

Captain Scarlet and the Mysterons season 1 episode 5, titled "Avalanche," finds Spectrum on a mission to investigate the mysterious disappearance of a nuclear-powered snow vehicle in the Swiss Alps. The driver of the vehicle, a Dr. Giadello, was transporting a new fuel element, which if fallen into the wrong hands, could prove disastrous.

Captain Scarlet and Captain Blue, along with a team of Spectrum agents, embark on a perilous journey up the treacherous slopes of the Swiss Alps to find out what happened to Giadello and his snow vehicle. Along the way, the team encounters a variety of obstacles, from treacherous terrain to bitter cold weather.

As they search for clues, they discover that Giadello's vehicle was sabotaged, and they must race against time to find the culprit and prevent the new fuel element from being used for evil purposes.

Meanwhile, the Mysterons, the show's main antagonists, are monitoring the situation closely and decide to intervene. They use their powers to create a massive avalanche, putting the lives of the Spectrum team in grave danger. The team must now fight to survive against both the natural elements and the Mysterons.

In the end, the Spectrum team manages to overcome the odds and stop the Mysterons' plan, but not without a few close calls along the way.

Overall, "Avalanche" is a thrilling episode of Captain Scarlet and the Mysterons that showcases the show's high-stakes action and sci-fi elements. The episode also highlights the bravery and resourcefulness of the Spectrum team, who are always willing to go above and beyond to protect the world from harm.