Nothing could be more exciting than a night flight on Bill's plane! But Philip, Dinah, Lucy-Ann and Jack soon find themselves flying straight into a truly amazing adventure. What has happened to Bill? Who are the two strange pilots, and what is the secret treasure hidden in the lonely valley where the children land?
There's no pussy-footing around with the opening scenes of the third book in the Adventure series. The children arrive back home after a trip in Bill's new plane (which he's been assigned to help him with his job, the lucky blighter!) and are terribly excited about the whole thing. Bill announces he'd like to take the children on a night flight to his home, and stay for a few days. Naturally the gang are over the moon! But, in Chapter 3, something goes horribly awry and the children end up in the wrong plane—with two obviously bad men at the controls. So, by Chapter 4, the children are marooned in some valley in the middle of nowhere in a foreign country!