Biggles and Bertie (for once Ginger is left at home) head to India to try and find Algy. He has disappeared whilst trying to uncover a gold smuggling operation.

After falling foul of the gang's attempts to kill them in their beds, Biggles and Bertie find Algy being nursed in the Terai by a retired soldier. He had been shot down by the smugglers and, badly wounded, was unable to make his way back to civilisation. However when the team drop in for a visit he explains the scam - Mr Larta has a hollow leg he pops over to the secret airstrip to fill occasionally. Armed with this knowledge the team spring a trap and capture the whole bunch soon after another gold drop-off.