The family are on a river boating holiday in Turkey when Bill gets a call from Sir George. Will another holiday be ruined? Bill is instructed to gather information on a small time criminal who is linked to a larger gang and a stolen quantity of a deadly chemical.

We are introduced to the orphans, Jack and Lucy-Ann Trent and their cockatoo, Kiki. Whilst on holiday, they befriend Philip Mannering and his sister, Dinah. Together they explore the uninhabited Island of Gloom, as a dangerous adventure awaits.

In The Circus of Adventure the kids are looking forward to a summer break now school is over and are soon off on holiday with Bill and Allie. But Sir George has asked Bill to protect the future Prince of Tauri-Hessia who subsequently joins the kids on holiday. Soon the family is thrown in to a daring adventure as they are pursued by the baddies who plan to overthrow the King and place a puppet Prince Tauri-Hessia on the throne.

The family have come to Wellington, New Zealand for a combined holiday and business trip. They are met by Bill’s friend, another agent, called Dennis. Dennis would like Bill’s help to solve the mystery of a missing agent who is investigating the movements of the arch villain, Perez. With Bill kidnapped, the children, marooned far from the mainland, find themselves playing a dangerous game of hide-and-seek with an unknown enemy.

The Woods Of Adventure. Jack and Lucy-Ann explore a mysterious castle, but a sinister young man confronts them and kidnaps their beloved pet cockatoo Kiki.

The Valley Of Adventure. Philip, Dinah, Lucy-Ann and Jack find themselves flying straight into a truly amazing adventure on a visit to Scotland.

The holiday this time is to be in the Black Mountains. Allison is going to paint and stay at a chalet, Bill will be working, but visiting, and Hans will take the children on a pony trek for a couple of days. With the mystery of a rumbling mountain, roaming wolves, and a mad genius who plans to rule the world, the trip does not turn out as peaceful as expected.

Bill and Allison’s wedding plans are put on hold as Sir George orders Bill to drop everything and get on the trail of a villain called Slade. To cheer Allie up, the kids suggest she joins them on a cruise and they soon set sail.