The story:
Relaxing on Eden, the Phantom, Rex and Tomm witness an oil tanker being stopped in its tracks by a helicopter crew threatening to fire bomb the ship unless a large ransom is paid. With the onlookers unable to intervene, the blackmail succeeds and the helicopter vanishes without a trace.

A second attempt on the same tanker is made a few days later when the Phantom visits the Mori tribe, this time with fatal consequences. However, the mention of oyster beds provides the Phantom with an unlikely but valuable clue to the tanker jackers' hideout...