Isabel Allende, a disciple of passion and beauty whose many works of fiction and nonfiction have never quite lived up to her 1982 masterpiece, "The House of the Spirits," recently decided to retire, she has said. Her agent talked her out of it and into co-authoring a novel with her husband, a mystery writer. When that failed, she set out to write a crime story by herself.

The result is "Ripper," a sprawling roller coaster of a mystery that could not have been written by anyone else. Set in San Francisco, it features a large cast of eccentric characters and a series of theatrical murders of people who seem to have little in common other than their general unlikability.

Amanda, a brilliant, shy girl, leads a group of quirky fellow teenagers in an online game called Ripper. They set out to solve the murders, (implausibly) doing a better job than the city's homicide detectives, led by Amanda's father. It's all an elaborate game until Amanda's mother, Indiana Jackson, disappears, apparently into the hands of a serial killer.

Despite the graphic nature of the homicides, the novel's tone is upbeat, almost merry. That works, but a couple of other things don't, as Allende falls into some bad habits she's developed in more recent novels. Each character is thoroughly psychologically analyzed, generally before he or she even gets a chance to say a word. And the narrator often digresses to earnestly educate us about social and political causes dear to Allende's generous liberal heart. Even for readers who might agree, this is annoying and anti-literary.

And yet her storytelling genius salvages the narrative and ultimately does what she set out to do — write a rip-roaring, entertaining crime novel. Three things make it worth our time and respect.

First is the character of Indiana, of whom Allende writes: "She measured happiness using a simple equation: One good day plus another good day equals a good life." The New Age healer is voluptuous and kind, a complex amalgam of wisdom and naiveté. Her tangled love life; her tenderness for Amanda, the daughter who couldn't be less like her, and her social and inner lives are well relayed.

Second, Allende succeeds in embedding the killer among the book's many eccentric characters, and when the identity is revealed in the melodramatic final pages, we say, "Of course!" We might have guessed who it was, but we didn't, which makes this mystery a success.

Third, Allende remains a remarkable spinner of stories. Her prose is sparkling and graceful (except for those little sermons), her ability to portray passion and action undimmed. "Ripper" grabs you, toys with you, amuses you, and even for those of us who prefer her earlier works but respect her right to try something different, that's good enough.

Pamela Miller is the Star Tribune's west metro team's editor.