The Goodies find a man about to commit suicide by jumping off a bridge and talk him out of doing so. It turns out that the man is the zookeeper in charge of in the brand new Monster House at the London Zoo who is depressed because he does not have a monster to put into it. Queen Elizabeth II and the Royal Family are coming to the grand opening in a few days, which prompts Tim to promise to find a monster in hopes of getting an OBE. Tim, Bill and Graeme decide to go to Scotland, where they hope to be able to catch the Loch Ness Monster for the zookeeper to put into the Monster House. When they arrive in Scotland, they shop for supplies to help them catch the monster, and the tourism agent makes them spend a lot of money by selling them a huge number of assorted supplies for the job. They hunt for Haggis, which runs away from them, raise a family of sporrans, and Tim is put into danger by the venomousBagpipesspider before Graeme kills it. Later, when Tim sets up to fish for the Loch Ness Monster, he finds it difficult to use the enormous fishing rod as well as having difficulty with the huge number of supplies which he has purchased to bait the hook of the fishing line. Graeme and Bill are also experiencing problems with their purchase of heavy diving suits and diving helmets. Descending into the depths of Loch Ness, Bill and Graeme discover that Tim is also there. Tim, who has not bought a diving suit, is holding his breath, an umbrella and a huge egg which he has purchased from the tourism agent. Graeme and Bill realise that it has all been a scam and, advising Tim to leave the giant-size egg behind, they discard their heavy diving gearto go to the surface of Loch Ness. It is there they find what they have been looking for, as the Loch Ness Monster surfaces slowly under them. The Goodies are delighted at their find, and set about taking their quarry home with them to Cricklewood. It escapes from them a few times but they manage to tie it to the roof of several taxis and get it to the office. The zookeeper is thrilled, and even more so with the egg, until Tim explains it's just a souvenir. However, the Zookeeper doesn't mind because he's learned that another monster was recently found and put into a zoo in Russia, and that there are hopes the two zoos can get them to mate. This prompts "Nessie" to panic and reveal that "she" is in fact the tourism agent in a huge mechanical costume and that to his knowledge there really is no monster in Scotland at all. The depressed Zookeeper returns to his bridge to jump into the river, but the Goodies call him back when the egg hatches in Graeme's arms to reveal a genuine, live baby Nessie which he can put in his zoo.
