Perhaps magic runs in some families. In KNIGHT'S CASTLE, we meet the children of Katharine and Martha, who run into a bit of magic themselves.

Martha's kids, Anne and Roger, must stay with their Aunt Katharine and their cousins Eliza and Jack while their father is in the hospital. Unfortunately, "[t]he last they'd seen of Eliza she'd been just about the bossiest nine-year-old girl on her, or any other, block. As for Jack, all he cared about was his Leica camera, and spent all his time in his darkroom, only coming out for meals, or, as Ann once said wittily, to cast his shadow, like Groundhog Day." The cousins bond, however, over their love of Ivanhoe and Aunt Katharine's present to Roger: a marvelous castle.

After Roger wishes on his most prized soldier, called The Old One, strange things begin to happen: "The castle was there, all right, but it seemed hundreds of times bigger, and yet at the same time it seemed hundreds of times farther away. And then Roger looked down, and saw that he wasn't in his room at all." The castle, of course, is magic, and the four children find themselves immersed in the days of Ivanhoe.

Eager has fun with his farcical land, replete with Robin Hood and his merry band, the nefarious Brian de Bois-Guilbert and Maurice de Bracy, the simpering Rowena and the lovely Rebecca. What the children play during the day becomes colorful reality at night, and they brush elbows with literary creations who speak a hilarious mix of old and new English ("'Never did Brian de Bois-Guilbert quail before witch or warlock. I defy the foul fiend. And besides, I don't believe it, anyway'"). Eager deftly slips in quotes from Shakespeare and references to The New Yorker and great books --- readers will feel no annoyance at such serious fare; the adventures rule the day.

   --- Reviewed by Emma Chastain