When zero visibility forces Biggles to land his Vandal amphibian aircraft on the North Sea he thinks he's just got a spot of aeroplane bother. Bigger trouble is ahead for Biggles when he takes an unchartered ride in a flying boat manned by 'Blackbeard' - a cohort of the Russian Airfleet and accomplice in a plot to bomb Britain.

'Well if you want trouble you can have it!' grated Biggles through set teeth. 'See how you like this!'In the later stages of the First World War Biggles and his fellow fliers have to use all their wit and skill to stay ahead of the German fighters so determined to bring them down.

'You're out last hope, Bigglesworth,' said the Air Commodore, with something like despair in his voice. The war supply route between Calcutta and China is a vital one but something is attacking the planes that fly it. Again and again pilots set off, only to disappear somewhere along the line, never to be seen again. When Biggles and his team are called in to investigatem, flying the route is close to a suicide mission . . .

'Don't move yet. I'm going out of the front door. They'll rush me then. That's your chance to go out the back way. Got that?'-'Quite clear.'-'Good! But don't think I'm exaggerating. My chances of getting out of here alive are about one in a hundred. Yours are one in ten. They'll kill you without the slightest compunction if they think you're with me. I don't know what you're doing here, but it doesn't matter. Make for London. If you get there, tell them what happened.'Biggles, Algy and Ginger accidentally arrive in Spain during the civil war. After a chance encounter with a British Intelligence agent who passes them a coded message which has to be got back to the Ministry of Defence in London, they are involved in a desperate chase to get back home with the evil chief of Intelligence and Propaganda after them.

A dull murmur, like distant thunder, reached their ears and brought Biggles to his feet with a rush. 'What is it?' he gasped.-At the first sound Dickpa had leapt for the flashlight. 'Quick,' he snapped, as the floor of the cave sagged sickeningly. 'Get out - it's an earthquake! Ah - stop!' he screamed. A visit to Biggles' uncle, Dickpa, lands Biggles, Algy and mechanic Smyth in a dangerous adventure looking for an ancient Inca treasure hoard.