Storm Catchers by Tim Bowler
Fin is devastated by guilt when his sister, Ella, is kidnapped. She is snatched away from the house in the middle of a storm. As the kidnappers make their demands, Fin's guilt is replaced by a fierce determination to find his sister by whatever means he can, and bring the criminals to justice. But as the drama unfolds, a complex web of family secrets is revealed, which will change everything, forever.