The Diamond of Drury Lane

The Diamond of Drury Lane is the first book in the Cat Royal Series by Julia Golding.

Plot
While escaping a riot in the theatre, Cat follows Mr. Sheridan into the depths of the theatre. She witnesses him and Mr. Marchmont discussing a diamond that will be hidden in the theatre. The men catch her, but trust her to help protect the diamond.

Pedro, a former slave, is brought to the theatre as a violinist/performer for a new show, which involves an "hot-air balloon" landing on the stage. However, the effect is having several problems. Cat offers to ride in it as a test. As she goes up, one of the ropes breaks and is left hanging on the side of the basket. Pedro helps her down safely. After a small argument where one of the orchestra members insults Pedro, he flees. Cat follows him, and finds he is being harassed by Billy Shepard's gang. She saves him, and the two return to the theatre. While the two talk, she accidently mentions the diamond to Pedro. He takes an interest, and tells her they will protect the diamond.

That night, Pedro has a triumphant debut on the stage, performing well and saving the show when the hot air balloon starts to fail. While everyone congratulates Pedro backstage, the Duke of Avon and his children congratulate Pedro themselves. Lady Elizabeth invites Pedro to entertain her friends at a party, and then invites Cat after Pedro tells her that Cat writes novels. She works on her new piece, which is illustrated by her friend Mr. Johnny Smith, the prompter that arrived at the theatre after the riot.

The two go to the party. Cat's work shocks many of Lizzie's guests, especially "Marzi - Pain" Marchmont, who claims it is unsuitable for his sisters to hear. After everyone leaves, Lizzie's brother Frank questions Cat about how real her work is. Pedro offers to take Frank to an actual boxing match, featuring Cat's long-time friend Syd Fletcher. Frank happily agrees, but Cat tries to convince the two it is a bad idea. She ultimately decides to accompany the two nevertheless.

The trio, with Frank disguised as a chimney sweep and Cat disguised as a boy, attend the boxing match and meet up with Syd's gang, The Butcher's Boys. One of the gang members, Nick, and Frank laugh over a new political cartoon done by the notorious Captain Sparkler, who has been producing several highly-insulting cartoons of the king. Cat realizes who the cartoonist is. Syd is victorious in the match. While going to congratulate him, Cat is separated from the group and runs into Billy. He invites her to join her gang. She refuses, and the gang bullies her. Frank walks in, and is also bullied by the gang. Syd and the gang come to their rescue.

When Cat returns to the theatre, she tells Johnny that she knows he is Captain Sparkler. He becomes angry with her, doubting if he can trust her. Later that night, she goes in search of him, but finds an intruder in Mr. Sheridan's office. She storms in and finds the intruder is Pedro, who has been searching for the diamond. Pedro wants them to find the diamond and become rich, but Cat sees it as stealing from Mr. Sheridan, who brought her into the theatre when she was abandoned as a baby. The two have a fight.

A messenger finds Cat and tells her Pedro, who has been exploring London with Frank, has been seriously hurt. The messenger takes Cat to Billy's headquarters, where it turns out that Pedro is not mortally wounded. Billy has heard about the diamond in the theatre, and interrogates Cat about it. She pretends to know nothing. Johnny, who had seen Cat and messenger leave the theatre, comes to her rescue. He convinces the gang that Cat knows nothing about the diamond, and threatens to kill them if they don't let Cat go. They let her go, and she and Johnny go home to the theatre. The two make up.

Lizzie, Frank, and "Marzi - pain" visit the theatre. He inquires about Cat's drawings in her novel. Pedro tells him that Johnny produced the pictures. After the guests have left, Johnny reveals to Cat that he and Lizzie had been courting before he ran away. He asks Cat to deliver one of his new cartoons to the printer. She obliges, and leaves for the printer. She runs into "Marzi - pain," who is at the printer's looking for a popular Captain Sparkler cartoon. He realizes Cat is delivering a new one, and "offers to escort her home." He forcibly does, and interrogates her about the new cartoon. They run into Frank and Pedro having a snow ball fight. Frank hits "Marzi - pain" and gets Cat out of his clutches. Cat informs Frank that "Lizzie's friends" is in trouble.

The trio heads to the Avon's home to alert Lizzie and figure out how to help Johnny. Lizzie offers to pawn some of her jewels for money to get a ticket to America for Johnny, and Cat will take them to the pawnbroker. Despite a brief meeting with the thieving Jonas Miller, Cat successfully pawns the jewels and get forty pounds for them. However, Johnny refuses to take the money. The Earl of Ranworth, Johnny's father, comes to Mr. Sheridan about his son's whereabouts. Mr. Sheridan claims to know nothing. A Bow Street Runner (police officer) arrives to search the premises after an "anonymous tip." Cat fetches Johnny and tells him to run for it. She burns the work he had done, and tells the runner, Mr. Sheridan, and the Earl that she has been taking lessons. The runner leaves, having a fruitless search. The Earl sees a bit of paper with Johnny's signature, and realizes that Mr. Sheridan has been hiding him. Later that night, Johnny returns. Cat realizes the diamond is Johnny, and not a real diamond.

Cat wakes up in the middle of the night, hearing intruders. She hides, while two of Billy's gang members search her room. They take her forty pounds. Billy finds Johnny and tortures him, trying to find the diamond's whereabouts, thinking it is an actual one. Pedro and Cat create a scheme to save Johnny. She finds Billy and tells him that she will join his gang. He buys it, believing her story of taking the diamond to a pawnbroker and getting money for it. She mentions that two of his gang members stole her money from it, and he takes it. She lures Billy onto a trapdoor the other boys under the balloon. Pedro opens the trapdoor and releases the balloon. They rescue Johnny and flee to the Avon's home. They smuggle Johnny into Frank's room while Cat spends the night in Lizzie's. They disguised Johnny as a women and send him off on a ship bound for America. A runner catches up with Cat and arrests her for supposed theft. She's put in a cell with Billy, who had told the runners that they were both thieves. Lizzie, Frank, and their father visit Cat. The Duke is under the impression Cat was intentionally stealing from Lizzie, despite his children's please that Cat was doing no such thing. However, they can't tell him what the money was actually for, so they have very little arguments. Frank lies and says the money was supposed to pay for his gambling debts, and while the Duke believes this, he stills believes that Cat wronged his children. She is taken back into her cell. Pedro and Frank go outside her cell that night while Billy is asleep and give her food. The next morning, the Earl of Ranworth has Cat released, telling the runners the money had been from Lizzie to his son, and that Cat is not a thief. He takes her to the Avon's home and explains the ordeal to the Duke, who drops the charges. Cat returns to the theatre, all of her friends happy that she is home.