SEALED WITH A SECRET

A 12-year-old Londoner hopes that solving a 75-year-old puzzle will mend her relationship with her big sister.

The blonde, white English friend from My Secret Guide to Paris (2014) stars in her own adventure. A week after returning from Paris, Phoebe's exasperated with her sister, Alice, who talks of nothing but her Parisian romance and her university applications. A flea-market find from the holiday—one Phoebe suspects is worth rather more than the 10 euros she paid for it—gives her the seed of an idea. Hidden in the antique Cartier compact is a letter from a girl in 1941 to her sister, a wartime evacuee living in the countryside. The letter contains a puzzling series of steps that will "bring two people together"; could it mend the relationship between Phoebe and Alice? Though she's a native, Phoebe takes a tourist's view of London as she follows the magical instructions, whether it's making a wish in Trafalgar Square or traveling from Kensington Gardens while reminiscing about the marriage of Prince William and Kate Middleton. History lessons abound; one construction worker who opens with informal and dated slang ("crikey") later recites a tidy, encyclopedia-style summary of the history of Wilton's Music Hall.

Not meaty but an entertaining, comfortably predictable path through solving the puzzle of sibling rivalry