350. Episode One 19.05.1973 5.50pm - 6.15pm 9.2M/18th 351. Episode Two 26.05.1973 5.50pm - 6.15pm 7.2M/38th 352. Episode Three 02.06.1973 5.50pm - 6.15pm 7.8M/29th 353. Episode Four 09.06.1973 5.50pm - 6.15pm 6.8M/32nd 354. Episode Five 16.06.1973 5.50pm - 6.15pm 8.3M/15th 355. Episode Six 23.06.1973 5.50pm - 6.15pm 7.0M/30th
Edited Compilation Thu 27.12.1973 4.00pm - 5.00pm 10.45M/44th Episode One Sun 02.01.1994 12.00pm - 12.25pm 1.31M ~ Episode Two 09.01.1994 12.00pm - 12.25pm 1.15M ~ Episode Three 16.01.1994 12.00pm - 12.25pm 0.84M ~ Episode Four 23.01.1994 12.00pm - 12.25pm 1.12M ~ Episode Five 30.01.1994 12.00pm - 12.25pm 1.29M ~ Episode Six 06.02.1994 12.00pm - 12.25pm ~ ~ - on BBC2
The Doctor investigates the mines, and finds a group of giant green maggots, and green slime pumped into the mine from the refinery. Meanwhile Jo has fallen in with the ecologists, and looks at some of their work, which includes a form of fungus that can be used to make a variety of different foods.
When the refinery director, Stevens, is confronted by the Doctor and U.N.I.T. he refuses to comment. The Doctor later uses a disguise to enter the factory and find out what is on the top floor. There he finds the real controller of the refinery - BOSS - a giant computer who has taken over the mind of Stevens.
BOSS plans to take over the world by linking itself to every other computer in the world. Using a crystal which he got from Metebelis 3 the Doctor manages to break the computer's hold over Stevens, who reprograms it to self-destruct. They find out by accident that the giant maggots can be killed using Professor Jones's fungus, and eventually they are all destroyed.
Professor Jones tells of an expedition he is planning down the Amazon, and asks Jo to go with him. Jo accepts, and parts company with the Doctor and U.N.I.T.
Episode 2: In the fight scene with the security guards, Pertwee's double is wearing the wrong colour wig.
Episode 2: When the Brigadier phones Professor Jones looking for cutting equipment to rescue Jo and Bert from the mine, Jones suggests asking Global Chemicals instead, since he tried to borrow some from them several weeks ago. But when the Brigadier is talking to Stevens at Global Chemicals and mentions the Professor, Stevens says something like: "Ah yes, he came looking for our cutting equipment yesterday."
Episode ?: Jon Pertwee mispronounces "chitinous" (i.e, mollusc-like) - the first syllable should be pronounced 'kite', but he says it as 'chit'. Afterwards, the production team received a letter that said: "The reason I'm writin' / Is how to say chitin."