The Goodies are taken to a lighthouse for 5 years since Graeme signed them up for it, although Graeme then confesses that he thought the advert said "A little light housekeeping".

The lighthouse they are taken to is the sinister "Jollyrock Lighthouse", where lighthouse keepers have been disappearing. The Goodies enter the lighthouse via a zip-line, with Bill coming last in a large pair of underpants. Tim immediately proclaims himself 'Number 1', with Bill and Graeme as 'Number 2's'. Tim orders Graeme to light the lamp which, after some complaining, he does. Graeme tries to read a book by the lamp, creating interesting artistic animal shadow shapes as he tries to follow it around.

Bill objects to everything in the lighthouse being round. Even the cards and chessboard are round. After Tim serves him a round lemon meringue pie, Bill chases him around the table, eventually splattering him with it. Graeme comes back down with his clothes in tatters, having been ravaged by moths. Bill then finds a book of sea shanties, in which they discover a song about the Jollyrock, which they commence to sing, in the hopes that it will lift their spirits, Unfortunately it has the opposite effect, as they discover when they begin singing, as the song graphically tells of the terrors of the Jollyrock.

Tim is then forcibly quarantined in the lamp room. Bill and Graeme are enjoying themselves playing cards while Tim is up in the lamp room bellowing about being stuck up there on his own. When Bill And Graeme listen to the radio for a forecast warning, they go to tend the lamp as Tim crashes in, bellowing "I SAID CAN YOU HEAR ME?!". Bill asks what's the matter and Tim explains that the lamp has gone out. Graeme inspects the problem as Tim and Bill try to fix the lamp. They find out that it wasn't busted, but just run out of oil. The Goodies couldn't get some fuel because Bill had thrown the great big barrel of oil away by mistake, thinking it was Cooking Oil — even Tim's baby oil is not enough to run a 10 million candlepower lamp, so Bill wears a candle on his head to go round in circles, while Tim and Graeme try to find some way and something to warn the ships. Tim comes up with the bright idea to warn the ships by launching a rocket, but he mistakingly lights-up the rocket inside the lighthouse instead of outside. Graeme bellows "AHH!! NOT IN HERE YOU FOOL!!!", and panics as he and Tim desperately try to get rid of the rocket by throwing it out of the door but the storm is too strong, so they go through the window. Tim holds the rocket but doesn't let go of it, and he and the rocket zoom out of the air and Tim is dumped back on the glass roof of the lamp room.

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Wikipedia