The Secret Mountain

The third story commences with Captain and Mrs Arnold setting off on another long haul flight, this time to Africa. The four children are allowed leave of absence from their schools to see them off, though Prince Paul, who since meeting the children has been sent to the same school as Mike and Jack is not allowed to accompany them. It's predicted that The White Swallow (the Arnold's plane) will break new records and there is much press coverage of the flight. Predictably and in an echo of what happened in the story of The Secret Island, on the third day the Arnold's plane disappears.

The Arnolds, we learn, do live in London and unusually for Blyton characters, in a flat. Also unusual for Blyton, despite the fame of the Arnolds as pioneering aviators, they do not have the usual retinue of servants. When around six weeks after the Arnolds are lost and the children return home for half-term, Dimmy is there to look after them.