The story:

(This story should be read in conjunction with D036 The Thuggees.)

The Phantom is on his way to see Diana, unaware that the plane he is passing in the night carries Diana in the opposite direction, and that an ancient sect called the Thuggees, led by the ruthless Prince Kali, is about to command her plane.

Having arrived at the Palmers, the Phantom soon learns that a huge ransom is to be paid for Diana's safe return. Following the kidnap trail, the Phantom swaps places with another intended kidnap victim, the wealthy Prince Tydore, before reaching The Thuggees' secret island, where the final battle takes place.

But more trouble lies in wait for the Phantom and Diana. Prince Tydore repays his liberator by trying to drive a wedge between Diana and the Phantom so that the latter can be married off to the prince's young and beautiful daughter Tari...