Number 22 in canonical order. Also exists in a version with the cover title "Flight 714 to Sydney." Also exists in a version with the Joy Street-Little, Brown trademark.
Tintin; Snowy; Captain Haddock; Professor Calculus; Laszlo Carreidas [Mr. Carreidas]; Skut; Paolo Colombani; Spalding; Gino; Hans Boehm; Allan; Rastapopoulos; Dr. Krollspell; Sondonesian nationalists; Mik Kanrokitoff; Jollyon Wag
Synopsis
Traveling with billionaire Laszlo Carreidas, Tintin and his friends are highjacked by Rastapopulos, who tries a truth serum to extract valuable information from Carreidas. Tintin and the others fight their way free, guided by mysterious inner voices that lead them deep into volcanic caverns beneath the island. The voices come telepathically from Kanrokitoff, who is in regular contact with extra-terrestrials. He rescues Tintin and his party from villains and volcanoes, but wipes their minds of the memory.