In The Dark Portal, Jupiter's plan (eventually foiled by the mice) is to unleash the Black Death on London once again. The prequel, The Alchymist's Cat, takes place in the 1660s during the Great Plague. Jupiter saw firsthand the devastation the plague wrought, so it makes sense that he would choose to use it for his own devious ends.
Woodget may initially seem like a rather odd name for Thomas Triton's fieldmouse best friend. However, it is referring to Richard Woodget, the former captain of the Cutty Sark. As anyone who has read the Deptford Mice books knows, Thomas would make his home inside the famous dry docked sailing clipper upon his retirement.
In Thomas, the titular character and his friend Woodget encounter an army of mongoose warriors, led by Captain Chattan Giri. They are battling the evil serpent cult of Sarpedon. This is incredibly fitting when you consider that mongooses are well-known for fighting and killing venomous snakes in Real Life.
Kempe the pedlar from The Crystal Prison shows Twit and Arthur some mouse figurines carved out of wood that were traded to him. He says that he was told that they were made by "a holy mouse what lived up in some mountain or other". When you read the epilogue of the prequel, Thomas, you realise just who this mouse was... the amnesiac Woodget, who became the Holy One of Hara after being rescued by Zenna. This is confirmed by an entry in The Deptford Mice Almanack.
The heroine of the main trilogy, Audrey, loves to dress in ribbons and lace. Etheldreda (or Audrey) was a 7th century saint in whose honour an annual fair was held in Ely, Cambridgeshire, and there her admirers would buy lace goods. But by the 17th century, this lacework was viewed as old-fashioned, cheap, and of poor quality, at a time when the Puritans of eastern England looked down on any form of lacy dressiness. This is where the word tawdry originates, shortened from tawdry lace, originally a corruption of Saint Audrey lace. How appropriate, then, that a character named Audrey would wear lace!
Vesper finding Ysabelle in the hidden chamber deep beneath the Hallowed Oak in The Oaken Throne, and doing so quickly enough to rescue her from the hungry toads, seems very unbelievable. Definitely a Deus ex Machina. But on the other hand, considering he's a bat, maybe he used echolocation to find her.
In The Dark Portal, Jake wins a battle with Fletch in the forgotten temple of the Raith Sidhe. He says he doesn't have time to bloody-bones his opponent for Hobb, so he instead snaps his head off in tribute to Bauchan. The last book of the trilogy, The Final Reckoning, has Bauchan making an appearance... a direct result of his being summoned by the sacrifice.
After Hobb is imprisoned in the acorn at the end of The Oaken Throne, Ysabelle explains to Vesper that it must be planted so an oak tree will grow. While a twig or leaf of that tree remains and a squirrel sits upon the Oaken Throne, Hobb cannot escape. So when Audrey, a mouse, becomes the Starwife at the end of the original Deptford Mice trilogy, it is no wonder that this change in tradition has set in motion a chain of events that will lead to Hobb's return when the Sequel Hook is followed up on. When the Great Oak (the one grown from the acorn) is blown over in a storm in The Deptford Mice Almanack, the squirrel subjects of the Starwife complain that it happened because she is not a squirrel but "merely a mouse". They might be on to something there...
In Whortle's Hope, Samuel Gorse's gift from the watervoles is a biscuit that will make him gain weight. This is something he wants because he is teased for being skinny. However, he gives the biscuit to the unsuspecting Dimsel Bottom so she'll be forced to drop out of the raft race he wants his friend Whortle to win. But Dimsel gains an immense amount of weight all at once, to the point where she is rendered helplessly immobile. Perhaps it was for the best that Samuel didn't eat the magical biscuit, as that fate would have befallen him. He wanted to gain weight, but not that much, surely.
