The year: 2020. The Terrahawks Organisation is mounted and they are ready to defend Earth against hostilities. When an energy source is picked up heading for Earth. Lt Hiro and his robot Zeroids blast off - but fail to destroy it.
The Hawkwing and Battlehawk are launched to investigate, but Ninestein is captured by Zelda, who uses him as a hostage in a bid to escape - but Hiro frees Tiger.
When Zelda releases one of her allies, Lord Sram, from suspended animation and sends him to Earth. Sram is shot down by Kate Kestrel. But the alien survives the crash - and makes life very uncomfortable for Tiger Ninestein.
Master of disguise, Mold, a faceless alien, is sent to Earth by Zelda. He crash-lands in the Arctic and the form of Lt Hiro, to sabotage Earth's defences and allows Zelda to invade the planet.
When Spacehawk picks up an unmanned and unharmed space capsule, then finds it contains Yuri, a cuddly space bear, Mary Falconer and Kate Kestrel adopt Yuri as their pet - but the bear is really Zelda's agent.
Journalists Mark Darrol threatened to expose the Terrahawks. Zelda contacts him and puts him aboard a ship taking food to the Terrahawks' base. But Tiger Ninestein has his own methods of writing off this latest threat.
When an AS4 titanium ore carrier is drawn off course and Zelda places her cube robots on board, the Terrahawks find themselves up to their necks in trouble when the robots transform into a huge space gun and threaten a new dam.
Sergeant Major Zero and the Battlehawk destroy five of Zelda's cube robots in the Wild West county of Bad Water. But one cube survives and Zelda uses it to take over hill-billy Sam Oaky - and plan a shoot-out with Tiger at high noon.
Zelda tries again. This time she spends a second Lord Sram to Earth and the alien manages to sabotage the Overlander in a valley. He boards it and sets out on a collision course with a refinery.
Alpha Probe, first launched in 1999, returns to Earth and the Terrahawks are assigned to bring it to base, where the Zeroids begin to work on it, unaware that Zelda has secreted one of her cube robots on board - with a gravity bomb.
When Lt Hiro and Kate pick up a glass cabinet of mist and take it back to Hawknest. Mary finds herself confronting Sra. Hawkeye meets Moid, and Tiger finds himself menaced by the Sportilla.
It's Christmas Eve, but neither Ninestein or Zelda have time for festivities. Both are busy planning their strategies for their battle on the moon. On Christmas Day, their battle begins in earnest.
While they are searching for gold on Mars, two crewman from space transporter find themselves Zelda's prisoners. She holds them hostage until Ninestein agrees to come to her headquarters - to be executed by Moid.
