Description:The Secret Series is a collection of exciting action-adventure classics that relate trilling adventures of Arnold children, older Peggy and younger twin siblings Mike and Nora, who live with a harsh aunt and uncle after their parents are thought to have been killed in a plane crash."The Secret Island" – Aided by Jack, an orphan they have befriended, the Arnold children run away to an island on a nearby lake, and together they make a new home constructed with the branches of a willow tree."The Secret of Spiggy Hole" – The Arnold children discover that their parents are alive and reunite with them. The family goes on a holiday at the rugged Cornish coast with a family friend, Miss Dimity. Children get drawn into a kidnapping case as they discover a boy named Paul, Prince of Baronia, being held prisoner in a castle tower nearby."The Secret Mountain" – Captain and Mrs. Arnold are flying off in their plane, the White Swallow, and apparently have crash-landed in a remote part of...