"Cross, Double Cross," magical murder mystery, is sucking in the denizens of magic school - and they often don't survive the trip.
Paige is dealing with an irate gnomish professor, who wants to ban some book from the library for being politically incorrect, disrespectful to little people, or just plain violent.
Phoebe is back at work, and anxious to solve the romantic problems of the city - especially those of her sister Piper. She's not so happy about the budding romance between Brody and Paige, however.
Leo is suspiciously calm and collected now that he's an avatar. He wants to get back with Piper, and he asks Phoebe's help with planning, and Paige's help with babysitting.
Piper is having trouble shifting gears - she's used to dealing with tortured, guilty Leo, not confident, sunny Leo. She thinks his change in attitude is too good to be true.
When Paige discovers Professor Gnome hasn't even read one of the books he wants to ban, she suggests he do so. He starts with "Cross, Double Cross" by the Mullens Brothers, which is a mistake - the books sucks him in, then ejects his bullet-ridden corpse. As magic school is supposed to protect its residents, Paige is concerned. This has happened only once before, 20 years ago, when Eddie Mullens killed his brother and disappeared. When Paige brings Brody back to help her investigate, they open the book and discover it's not finished. They get to help finish it, when they get sucked into its world of tough-talking gangsters, corrupt cops, and no magical powers. Paige and Brody change into more period-appropriate clothing, then go searching for Eddie, reasoning since he's one of the authors, he must know how to get out. Paige and Brody are surprised to find Eddie as the hero of his own book, a detective looking for the Burmese Falcon. Eddie's brother Danny started writing the story, but it's taken on a life of its own now, and all the characters are obsessed with finding the falcon. So obsessed that a group of corrupt cops offed Danny.
When Phoebe and Piper go looking for Paige, they discover the book. Phoebe touches it and has a vision of the couple being sucked in, so the sisters take it back to the manor to consult the Book of Shadows and ask Leo for help. Leo opens the book despite Phoebe's warnings, but his fellow avatars keep him from being sucked in. Now the sisters can see the book as it's being written. They read that Eddie is leading Paige and Brody - now called "Lana and the Fed" - into a trap and try to help them by writing in a flat tire. That plot twist works, but Phoebe finds she can't write them out of the story altogether. Piper and Leo go talk to Eddie's parents while Phoebe tries to keep throwing in plot twists that will help her sister out. She inserts some dialog into a cop's mouth that prompts Paige to play the femme fatale, which allows her to steal his gun and free herself and Brody from the murderous cops. Paige is all for finding the falcon herself, but Piper and Leo discover that Dan started writing the book to help Eddie gain confidence - learn to be a hero. He's the only one who can end the story.
Brody figures out the story is still going on because Eddie feels guilty about his brother's death - he betrayed them to the gangster out of guilt and pain, not malice. The gangster captures Paige and Brody, and plans to kill them, when Eddie walks in. Phoebe writes in a flashback, so Eddie can see it's the gangster who killed his brother. Eddie retrieves the falcon from his safe, and breaks it, freeing them from the book.
The cover of the book changes - now the authors are listed as "The Mullens brothers and the Halliwell sisters." Eddie goes home to his parents, who never stopped hoping for his return. Piper agrees to try to start over with Leo. And Paige and Brody kiss, starting something of their own.