Children’s and teens roundup: the best new picture books and novels

A mellow lion, a beach party with sharks, a rooftop paradise and the curse of a superpower

There is a cool wind of adventure blowing through books for eight- to 12-year-olds this month, a welcome distraction from the heat. In Catherine Doyle’s magical fantasy The Storm Keeper’s Island (Bloomsbury), sea-fearing Fionn doesn’t want to go to Arranmore, leaving behind the familiar Dublin smog. But when the island chooses him as its new preserver, he’s drawn into a battle with an ancient evil at its roots. Acutely observed sibling dynamics, a house full of magical candles, and a vivid sense of history interwoven with Irish legend make for a standout novel, written in the vein of Susan Cooper and Pat O’Shea.

A different kind of fantasy is at play in Joanna Nadin’s Where Do You Go, Birdy Jones? (Little, Brown). Birdy doesn’t fit in at home, especially now Dad’s remarrying and ...