Following the clue found in Thunder Oak, the weasels journey to a city inhabited by quarreling squirrels.
Sylver and his outlaws set sail for the Island of Dorma, where the humans are reputed to be in a perpetual sleep.
Years after the return of the humans, the weasel detective Montegu Sylver attempts to solve the disappearance of a foreign dignitary while preventing his cousin from setting off explosives in the city.
- Sylver - The leader of the outlaw weasels.
- Mawk - A cowardly member of the outlaws
- Scirf - A scruffy but intelligent male outlaw.
- Icham - Sylver's closest friend and fellow outlaw
- Bryony - A female outlaw with a close relationship with Sylver
- Miniver - An undersized but resourceful female weasel
- Wodehed - An old magician whose spells go wrong more often than not
- Dredless - A male outlaw who is the most dangerous with darts or slingshot
- Luke- The holy male weasel of the outlaws
- Alysoun- A jill (female) outlaw who is the fastest runner in Halfmoon Wood.
- Prince Poynt - The spoiled and childish ruler of Welkin
- Princess Sibiline - Poynt's smug but friendly sister
- Sheriff Falshed - The high sheriff of Welkin
- Lord Flaggatis - A sorcerer seeking control of Welkin
- Lord Haukin - A kindly but forgetful old stoat
- Montegu "Monty" Sylver -
- Bryony Bludd
- Scruff -
- Maudlin -
- Spindrick Sylver - Monty's cousin, an infamous anarchist with a penchant for destroying things
- Jeremy Poynt - The Mayor of Muggidrear
- Sybil Poynt -
- Zacharias Falshed - The Chief of Police in Muggidrear
- Hannover Haukin -
The animals featuring in the series are primarily species native to England, though more exotic species are occasionally mentioned. The first book explains that in the years following the disappearance of all humans, the animals of Welkin, both those wild and once domesticated, made their way into the abandoned castles and villages, using what the humans had left behind. Gradually the animals learned to speak human language and, to an extent, use human tools. While some of the animals were content to live in the forest, the mustelids in particular adapted to a more civilized way of living. The otters and mink took to the riverways; the badgers kept to the subterranean territories; the pine martens stayed in the trees; of the remaining weasels, stoats, and now-feral ferrets, the stoats were the most ambitious and aggressive, and took control of Welkin.
- Titles - The weasels and stoats use the terms jack and jill to refer to males and females, respectively. In the second arc, the shortened forms Jal and Jis are used in the same way humans use the titles Mr. and Mrs.
- Hollyhockers - A popular form of gambling involving seeds thrown onto a surface in various patterns
- Halfmoon Wood - The forest where Sylver and his bandits live
- Castle Rayne - Prince Poynt's castle, once inhabited by the humans
- The unnamed marshes - The land of the rats, ruled over by the mad stoat Flaggatis.
- Muggidrear - The capital city of Welkin. It is split in half by the river Bronn. The south side is occupied by the humans, and the north is occupied by the animals.
- Whistleminster Palace - The castle where queen Varinder lives and where the royal family lives
The island of Welkin is populated not only by animals, but statues created by humans that have since come to life. The statues have the ability to talk, but most do so rather poorly and have only limited intelligence. All statues wander Welkin constantly in search of their "First and Last Resting Place," that being the quarry from which the stones they were sculpted from were cut, or the forest from which the trees used to carve them were grown.