In this magical story for young independent readers, Ophelia and her sister Alice have accompanied their father to a strange, wintry city where he's been hired last-minute to curate a sword exhibition at a museum. The girls' mother has died just months before, and it's clear that the girls and their father have all been somewhat lost since then. 
 When Ophelia wanders off to explore the museum, she finds a boy locked in a hidden room, who tells her a tale of a magical mission involving a lost sword, the Winter Queen, herald trees, and a protectorate of wizards. Ophelia is a scientific and logical girl, and can't bring herself to believe the boy's story. But her innate compassion, bolstered by her imaginings of her mother's voice in her ear, bring her to dedicate herself to helping the boy. 
 Ophelia isn't a typical heroine. She wears glasses that are always smudgy, and has to stop for quick puffs from her asthma inhaler whenever things get too exciting. Still, she has a big heart and avid curiosity, and so she keeps pushing herself to explore, to collect the clues hidden throughout the museum, and to find a way around the beautiful but menacing museum director. 
 Ophelia and the Marvelous Boy is a fantasy adventure set in the modern world, with magic embedded in a city full of people going about their business and not prone toward belief in evil queens or sinister spells. There are some wonderful touches: a portrait gallery of glum-looking girls sets an ominous tone, galleries of everything you could imagine which seem to change every time Ophelia passes by, museum guards who sit and knit all day until falling asleep, and an older sister who gives up her jeans and t-shirts for a mysterious beauty treatment. 
 I'm not sure that the climax and resolution of the book necessarily make sense, but it doesn't really matter. Ophelia is a lovely main character, showing unexpected strength as she pushes herself beyond her normal limits. As Ophelia and her family finally face the danger in the museum, they also finally come to terms with the loss that they've suffered and take the first tentative steps toward healing and finding a way forward without their mother. 
 There are some wonderful magical scenes, as well as moments of danger and excitement. This book should please middle grade readers who like action mixed with fantasy. The reading level seems appropriate for older elementary school grades, easily accessible for children confident in their independent reading abilities.