'The Stranger Within Sarah Stein' by Thane Rosenbaum: Book review Young adult novelists are increasingly tackling darker subjects: kidnappings, drugs, rape. But few have delved into so many dark subjects as novelist Thane Rosenbaum, who ventures into YA territory with his latest, "The Stranger Within Sarah Stein," a novel revolving around divorce, Sept. 11, homelessness and the Holocaust. What might be most odd about this combination of subjects is that the book isn't glum at all. Told through the eyes of the perky, bike-riding 12-year-old Sarah Stein, the daughter of a candy-making mother and an artist-painter father, it works as more of a fantasy than as a dark rumination on tragedy. There is sadness between the lines, but also a bright fairy-tale aspect, a kind of "Willy Wonka" meets "Extremely Loud & Incredibly Close." The book opens as Sarah's parents decide to divorce, forcing her to shuttle, on bike, between her father's loft in TriBeCa and her mother's new Brooklyn pad, near the chocolate factory (Carly Cocoa's Chocolate Factory - see what I mean about fairy tale?). Upset by her wrenched-apart life, Sarah slowly becomes two separate Sarahs, one who is girly but ditzy and lives in Brooklyn, another who is biker chic and lives in Manhattan. "I was just happy that the splitting had so far stopped at two Sarahs," she says about this transformation. What if I got divided one more time - the never-ending fractioning of Sarah Stein? Sarah is not taking the divorce well, but she finds an ally one day as she's crossing the Brooklyn Bridge. Upset by thoughts of divorce, Sarah crashes her bike into a homeless man who happens to live in a secret portal in the bridge filled with "cuckoo clocks and toy fire engines and a small replica of a volcano." He knows uncanny things about her, calling her chocolate girl and telling her she's running away from something. She sees a picture of the homeless man - who calls himself Clarence Wind - next to an article describing a decorated fireman disgraced after the bombing of the World Trade Center in 2001. Our Wind has a murky past, and though Sarah is scared of him, they decide to become friends. Wind's Brooklyn Bridge becomes a third home for Sarah as she moves between her parents, allowing her a stopping place to change clothes and personalities, and a friend to confide in. Neither of her parents notices that she's split her personalities: Sarah's grandmother, who we learn narrowly escaped the Holocaust, is the only other adult to notice her transformation. As Sarah becomes more confused about who she wants to be, Wind begins appearing everywhere - outside a nice restaurant where Sarah's family eats dinner or as a waiter at her father's art opening - but won't answer questions about his past. Instead, he gives her a melted piece of steel and some dust-covered rosary beads. As Sarah solves the mystery of Wind's past and learns what her grandmother suffered during Hitler's reign, she also becomes an unlikely hero at a9/11hearing, of all places. It's at this point that Rosenbaum's narrative may strain credulity for readers expecting a story more grounded in realism. But realism and fantasy have always merged in Rosenbaum's work, especially in his 2003 novel "The Golems of Gotham," and the same is true here. Rosenbaum is skillful at writing from a child's perspective about the very real challenges of divorce - Sarah describes her new schedule with her parents in a pitch-perfect way, describing how they had to split each holiday: "The days of the week were like properties on a Monopoly board. The calendar was a rulebook.... Life is no fun when you're on a timer. It's okay for an egg, but not a person. Watching sand drop into an hourglass can be nerve-racking, the granules falling too fast. It's all too rushed and you can't relax. The story tackles many large issues, but it's Sarah's story of struggling with her parents and her new life that resonates the most. Sarah's world is a colorful one barely marred by the tragedies the people around her have experienced, and she is a refreshing character amid young adult books filled with rebellious and scarred teens. That's why what might appeal to young readers here is the chance Rosenbaum gives us to follow a young girl, quirky and defiant, as she tries to reconcile the two people she is becoming since her parents' divorce.