The Secret of Spiggy Holes : Children's Adventure Novel

The Arnold children discover that their parents are alive and reunite with them. Also, their parents adopt their new friend Jack, who is an orphan. The family goes on a holiday at the rugged Cornish coast with a family friend, Miss Dimity. In a dangerous adventure, children get drawn into a kidnapping case as they discover a boy named Paul, being held prisoner in a castle tower nearby. Paul turns out to be the Prince of Baronia, a small, remote kingdom and kids become firm friends with him.