Joan Aiken 
Teeth of the Gale [EPUB ebook] 

"Don Francisco wants you home, and in double-quick time, too. We must leave tomorrow at dawn . . ."Felix’s heart sinks at Pedro’s words. What can be wrong? Is his beloved grandfather ill? Dashing and loyal, he speeds towards Villaverde — and a rescue mission.Donna Conchita’s children are kidnapped and Felix may be reunited with the feisty Juana, if he agrees to help. Despite warnings of a conspiracy and his own suspicions of a trap, Felix fearlessly plunges into a plot thick with intrigue and danger. His grandfather said it was a matter of life and death — but whose?