The Endeavour runs before Cyclone Ada, which devastates tourist resorts on the Great Barrier Reef and towns on the North Queensland coast. After the disaster, the Minus Five team return to the area to search for survivors, and play an important role in rescue work.

Minus Five picks up uranium readings which appear and disappear. A trawler hauls in a catch of fish which could be radioactive, but a more important 'catch' is contested with spear guns under the ship as the Endeavour crew stumble upon uranium smugglers.