This episode opens with the best shot of anything on television ever:
There. The Minister dictating to his secretary. In the nude! In a sauna! Every business meeting should be like this!
An anticlimax is inevitable. Yellow Fever breaks out on an island health farm. At the same time a maverick scientist is enjoying a second honeymoon on the island. And why have the spiders turned blue?
Turns out Maverick Scientist has a reputation for Not Thinking Things Through. He's made a virus that kills off moths. But the spiders ate the moths which triggered off a latent virus in the spiders which could destroy Penzance. Has the man never heard the song "I know an old lady who swallowed a fly?". Well, perhaps he'll die.
By the half hour mark, the Minister is out of the sauna, everyone's turning yellow, and the Maverick Scientist has gone to look for spiders down an old mine. What could possibly go wrong? Wronger?
Yup. The mine collapses! And it's full of blue spiders! And John Ridge is trapped down there with only a feather duster and sheepskin gloves to protect himself! But the good news is there's going to be a bumper crop of apples on the island this year...