The Amazing Maurice is a talking cat, who leads his Educated Rodents, a group of talking rats, as they go from town to town being a plague so that their accomplice, a boy piper, can "lure them all away" from the town, after which they share the money the piper makes. The rats had gained intelligence from eating the waste from the rubbish tip behind Unseen University (UU); Maurice gained it after eating one of the rats (before he realized that they're no longer proper rats).  The group is not completely happy; the leader of the rats, Hamnpork, despises Maurice, while Dangerous Beans, a near-blind rat who guides them like a guru, wants to start a rat civilisation and both he and Peaches, the group's scribe, find their trickery unethical. The rats are seeking an ideal of humans and rats living together, following the example of their sacred book "Mr Bunnsy Has an Adventure". They agree to do one last job, in the town of Bad Blintz, in Uberwald.  The rats set about planning their offensive, lead by Darktan (who in many ways resembles Justin in The Secret of NIMH), their general, while Maurice and Keith, the piper, look around. They are surprised to find that while the buildings are expensively built, the people have little food, and rats are hunted far more viciously than anywhere else. Maurice and Keith meet Malicia, the mayor's daughter, who is a story teller (her grandmother and great aunt were the Sisters Grim). She soon discovers that Maurice can talk, and meets Sardines, a tap-dancing rat who is the most daring of the group. While talking to her, Maurice reveals that the rat-catchers have been passing off boot-laces as rat tails (for which they are paid 50 pence each).  As they set off to look in the rat-catchers' house, the rats discover many rat tunnels, which are empty, save for traps and poison. The two groups meet in the rat catchers' den, where they have been storing the food the rats are thought to have eaten, and find cages where the rats are being bred, for coursing.  The rat-catchers return, and lock Keith and Malicia away, and take Hamnpork to be coursed. Maurice hides, and feels a voice trying to enter his mind. The rats feel it, and it returns many of them to being simple rats, to the dismay of Dangerous Beans. Darktan leads a group to rescue Hamnpork, while Peaches and Dangerous Beans free Keith and Malicia. Malicia lets slip that "Mr Bunnsy Has an Adventure" is a fictional children's book, and Dangerous Beans and Peaches leave in despair.  Darktan's group is successful in rescuing an injured Hamnpork, though Darktan himself, the head of the Trap Disposal Unit, finds himself in a trap. After a near-death experience, and the death of Hamnpork, he assumes leadership, and sets out after Dangerous Beans. Maurice, in the meanwhile, has given in to his conscience and is also seeking them, but the voice gains power over him. Malicia and Keith, after gaining freedom, trick the rat catchers into revealing their secret by tricking them into thinking they have been poisoned. The rat catchers have created a powerful rat king – several rats, tied together at the tail, who make a single mind with power over others – who is named Spider, being made of eight rats (eight being a magical number on the Discworld).  Spider is interested in Dangerous Beans; other rats he can control, but Dangerous Beans has a mind similar to his: one that thinks for others. Dangerous Beans refuses Spider's offer of jointly ruling, as Spider wants to wage war on humans. As this happens, Malicia and Keith, under Spider's control, are about to set free the trapped rats. Spider tries to destroy Dangerous Beans' mind; this is felt by his army of rats, and Maurice. Dangerous Beans is able to resist, but Maurice reverts to being a cat, and the cat instinct tells him to pounce on Spider, though enough of his mind remains to tell him to sever the knot in Spider's tails.  Darktan's army, who have been fighting Spider's rats, find Peaches in Spider's lair, which is burning after Peaches dropped a match. Maurice emerges carrying Dangerous Beans. When he is safely out, he falls over and dies. In ghostly form, he sees the "Bone Rat" coming for Dangerous Beans. He attacks him, but is picked up by Death, with whom he strikes a deal: one of his remaining lives for Dangerous Beans'.  Though Spider is defeated, there is still a problem remaining: the rat piper is due to arrive the next day. The rats set about rounding up the other, non-intelligent, rats ('keekees'). When the piper arrives, Keith challenges him. His pipe had been broken by the rat-catchers, so he uses a borrowed trombone, to the sounds of which Sardines comes out dancing. When the piper starts to play his magical pipe, the rats plug their ears to avoid being charmed. One rat does come out: Mr. Clicky, a clockwork rat the rats use to test traps.  The piper calls Keith aside, and tells him the tricks of the trade: the pipe contains a hidden slide position for a trick note that drives rats away, the stories are made up so people will be scared into paying. Keith and the piper then lead the keekees out of town – Keith wants to maintain the story of the piper, and the rats want a convenient way to set the keekees free.  Once that has been done, the rats emerge, offering to tell the humans where to find the stolen food and money, in return for living peacefully with them. Maurice negotiates, selling the humans a promise of a brighter future, with the rats as a tourist attraction. Keith stays on as the town's piper, and the town becomes a tourist attraction, as Maurice predicted.  Curiously, The Amazing Maurice and His Educated Rodents, and the scam they operate, are referred to in Reaper Man, but it seems that the UU wizards attributed Maurice's name to Keith.  All the rats' names derive from the words they have seen written on tins, and they have called themselves whatever they thought sounded good. That's what happens when you learn to read before learning what the words actually mean.

There's a lot of Witches Abroad in it, mainly the stuff about stories and endings, the cameo by the Grim Squeaker is good too, although to be honest there should have been other appearances by him earlier in the book, it just didn't feel right when he failed to turn up at the appointed moment. The ending too feels a little bit too abrubt, as if TP himself didn't know how to end it, or he ended it so many times in so many different ways that what was left was a sort of ending by committee. The main text though is classic Discworld, taking a simple tale like the Pied Piper of Hamlin and populating it with much more interesting characters (esp the Rats) and just letting them go to it...