Pollution, giant maggots, and the Doctor losing his best friend to a guy with a beard. Rough week.
Short Synopsis
In South Wales, a shady oil company is polluting everything in sight, which naturally leads to glowing green slime, giant killer maggots, and Jo Grant’s engagement to a man she met about fifteen minutes earlier. The Doctor saves the day but loses his companion — to a younger model.
Extended Storyline
The Doctor wants Jo to join him on a trip to Metebelis III, his favorite holiday destination for blue crystals and near-death experiences. Jo, however, insists on heading to Wales to investigate reports of mysterious deaths in a coal mine. Translation: “Sorry, Doctor, I’m going spelunking instead of space-traveling.”
Once there, Jo meets Professor Clifford Jones, an eco-activist, scientist, and proud owner of a very 1970s beard. He’s basically the Doctor, but with a guitar, flared trousers, and a few more protest songs under his belt. Sparks fly instantly, because apparently shared interests in ecology and hippie communes are all you need for true love.
Meanwhile, the Doctor begrudgingly follows Jo into the mine and discovers the real problem: Global Chemicals, a corporation with an evil computer boss named BOSS (subtle, that), has been dumping toxic waste into the environment. The waste creates glowing green sludge, which in turn spawns giant maggots. Because of course it does.
The maggots proceed to crawl around menacingly, attack people, and prove once again that cheap special effects can still traumatize children for decades. Eventually, the Doctor figures out that the only thing that kills the maggots is Professor Jones’s special fungus — which conveniently also doubles as a health food product. Eat your quinoa, kids, it just might save the world.
The BOSS computer tries to go full Skynet by linking itself with every computer on Earth (via an early ’70s dial-up scheme), but the Doctor foils the plan, wipes out the maggots, and saves humanity from death by green goo.
But while the Doctor is busy being heroic, Jo gets engaged to Cliff after about three conversations and a shared picnic. She decides to stay in Wales to marry him, leaving the Doctor heartbroken. The story ends with him driving away in Bessie, silent and alone, while every viewer at home sobbed into their tea.