The story:
With Diana due some leave before taking up her new job as head of the UN Bangalla office (see D143 The Tree House), the Phantom borrows a helicopter from President Luaga to fly the Walker family plus Rex from their new home in the treetops to the paradise island Eden.

On arrival, the Walkers make an astonishing discovery in the cave housing Hzz and Hrz, but that is not the only surprise that lies in store for them: a group of hunters have earlier located the island and are on their way back to claim their find...