The story is told in the form of a series of journal entries made by Beka Cooper as she trains to become a Provosts Dog, a nickname for the police men and women in the employ of the Lord Provost of Tortall, with a prelude taken from Eleni Cooper's diary in which she relates Beka's story to her son George.

Lord Gershom adopts her, her mother, and her brothers and sisters from the "scummer" life of Mutt Piddle Lane, where the very poor live.

Though the Dogs are initially unsure of their new charge, Beka proves to be a valuable resource, although she is extremely shy and has a hard time speaking in front of people.

She can also hear snippets of conversations that may contain valuable information caught by "dust spinners," beings made of breeze and dirt mixed from the city streets.

The other threat is an unknown party who keeps hiring digging crews to search for fire opals (rare and extremely expensive stones that not only have irresistible beauty, but supply mages with a certain power).

Beka's determination to see both parties brought to justice will place her in the middle of a power struggle in Tortall's underworld.

Tamora Pierce has noted in her blog that Pounce is the same character known as Faithful, Alanna's cat in the Song of the Lioness quartet.

However, he has the ability to speak, hear Beka's thoughts at close range when she wishes, and perform tasks most cats cannot.

Crookshank is a landlord who owns most property in the Lower City and is hated by everyone for his unfairly high rates and his cruel retaliation when rent cannot be paid.

Through her training as a Dog, her time spent with pigeons and Dust Spinners, and with the help of her friends Koramin Ingensra, Rosto the Piper, and Aniki Forfrysning (a mage, rusher, and a sword fighter who work for the Rogue, the king of crime in the city) Beka gains information about the opals and the Shadow Snake.

She soon discovers that it is Crookshank who has been hiring the diggers to be murdered, and the Shadow Snake is demanding a large number of fire opals.

Here they run piss!” The King, Roger II of Conté and Queen Jessamine live here in the palace with their new son, Prince Gareth.

Provost's house is here, and Beka visits every Sunday to see her little brothers and sisters, as well as to receive scoldings from Lady Teodorie, (Lord Gershom's wife), and praise from her husband.

(varies by district) Both Matthias Tunstall and Osgyth Yoav (Jewel's partner) are Senior Guards.

Because of her special abilities and her relationship and training with the Lord Provost, Beka begins the story with a rather arrogant attitude, assuming she will be promoted to full Dog faster than any Puppy in history.

He is vain and extremely sensitive about his age, getting angry when Beka calls him old and says he has white hair to distract him from flirting with her.

Rosto, Aniki, and Kora become very good friends with Beka throughout and into the story, even moving into her boarding house and sharing breakfast with her.

This flirtation comes to a head when Rosto defeats the Rogue and when telling his friends of his victory, kisses Beka in celebration.

They go to the Court of the Rogue to collect the Happy Bag (slang for a sizeable bribe, which the underpaid Dogs live on).

Develops a strong liking for Beka, and even defends her to the other Trainees (Puppies) when they start calling her “Fishpuppy”.

Lord Gershom of Haryse: Beka's adoptive father, who took in her whole family (six people) when she was just eight years old after she brought him the Bold Brass Gang.

A kind, understanding, patient man who loves Beka as his own daughter, and makes sure she gets the best in the Provost's Guard.

Has a no nonsense attitude with the Rats (criminals) who enter his court whining about family or debt, or the Dog who caught them.

He even defends Beka more than once, and encourages her, in his own way, to do her best with comments like, “While we live, Cooper.” Quote from Bloodhound: “If there is a betting pool, I will place a gold noble on Cooper,” Lord Gershom replied.