Tom and Jerry: The Space Giants - Beware of the Lugo Race

The Lugo Men and Zandosis
One night in Tokyo, Japan, a fireball i seen falling from the sky, Ito Mura and hiss assistant photographer, Liz, learn that the shooting star has landed in the northwest. They drive to the location and discover a yellow saucer. Convinced that the ship belongs to Rodak, Ito goes for help while Liz stays to take some photos. However, a mysterious black-colored figure appears from inside the saucer and captures her. Ito returns with the police led by Master Detective Droopy and his son Dripple, only to see the saucer explode and find Liz walking in a trance.

Mikko, his mother Tomoko, his friend Robyn Starling from Starling Enterprises in America and their pets, Tom Cat, Jerry Mouse, Spike and Tyke Bulldog visit the planetarium, where they and other children are learning about shooting stars, All of a sudden, Rodak's image appears on the planetarium "sky". He repeats his plans to conquer the Earth, because it is the most beautiful planet in the universe. In the confusion to leave the planetarium, Mikko, Robyn, Tom and Jerry are separated from Tomoko, Spike and Tyke. Tomoko and her bulldogs were followed by four other black people in a car, who then captured her and Spike. But Tyke has managed to escape their unknown enemies, and met up with Mikko, Robyn, Jerry and Tom. Moments later, "Tomoko" and "Spike" have finally returned much to their amazement. That night, while Mikko and his friends are asleep, "Tomoko" enters his room and takes his supersonic whistle given to him by Ambassador Magma. She blows the whistle many times. Thinking it to be an emergency, Magma, his wife Silvar, their son Gam and their pet mouse Nibbles (or Tuffy) all respond and travel from Mount Olympian to the Muras' house. Mikko, Robyn, Tom and Jerry are startled and they rush outside to see "Tomoko" along with "Spike" confronted by three robot people and one robot mouse. They are frightened until Mikko explains the use of the whistle. All agree that it was a mistake.

But the next day, Mikko, Robyn, Tom, Jerry and Tyke goes to Ito's office at United Press International and tells him that they left a tape recorder running in the house. As "Tomoko" and "Spike" calls Rodak for instructions, every word is being recorded. Robyn, the Muras and their pets come home and accuse "Tomoko" and "Spike" of being impostors. Realizing that they has been trapped, they transformed into a grey-colored, bald-headed creature in a silver uniform and a black-colored bulldog. The creature identifies himself as Venom, leader of the Lugo Men sent to take over the Earth, and after attacking Robyn, the Muras and their pets with his physical powers, he and his Lugo Dog, Killer, escapes by disappearing through a wall. Back in his spaceship, Rodak informs the world that his latest monster Zandosis is draining all the sound waves from the air and that a silent world will soon be a dead world. The Muras, Robyn, Tom, Jerry and Tyke take the tape recorder to Droopy, Dripple and the authorities and play the recording of the disguised Venom and Killer contacting Rodak. "Droopy" and the inspector, who unbeknownst to Robyn, the Muras and their pets are really Venom and Killer in yet another disguise, uses their powers to add a commercial at the end of the conversation, making the entire tape seem like a radio program. Magma and Silvar spot Zandosis in the ocean that has been destroying ships at sea. It is noted that when the monster is on the surface, there are no sound waves in the air.

The Muras, Robyn, Tom, Jerry and Tyke follow Liz, whose identity has been taken by a Lugo Man. They tail her by car to a deserted Jungle area where she meets Venom and Killer. They overhear Venom telling Liz that an army of Lugo Men, Cats, Dogs and Mice will soon arrive on Earth to take over the identity of humans and animals in the first step of conquering it for Rodak. The Lugo Warriors arrive in their saucers, and they demonstrate their ability to walk on water, By nightfall, they went to the Mura's house, and there find Gam and Nibbles, who have arrived earlier only to find their friends gone due to the struggle with Venom. The Lugo Warriors believe Gam is Mikko, but he and Nibbles fought the and melt them to their death with their Gamma Rays. Mikko, Ito, Robyn, Tom, Jerry and Tyke follow the Lugo Warriors (including one in disguise as Liz) to a local hospital. They see the real Tokomo and Spike being wheeled out. And to make matters worse, all the nurses at the hospital have been taken over by the Lugo race. Meanwhile, Zandosis shoots down the U.S. Navy patrol aircrafts.

The Lugo Warriors took all of their human victims in a truck for transportation to another location. Robyn, the Muras and their pets watch them, but are helpless to do anything. Ito orders Mikko, Robyn, Tom, Jerry and Tyke to keep observing them from their hiding place while he goes to the police for help. But the Lugo Warriors, back in disguise as the inspector, Droopy and their police officers through the use of their identities, has him thrown in jail when he unknowingly tries to tell them his story, They are about to steal Mura's identity when Silvar blasts in to rescue him.

Flying over the ocean shipping lanes, Magma spots Zandosis and begins to launch into attack. But the creature is too strong and escapes into the ocean depths. Magma returns to Mount Olympian and tells Methusan that the creature has escaped and that a better means of fighting the creature must be devised. Ito attempts to tell his bosses at UPI that Liz is the Lugo Man, but no one will believe him. Elsewhere, Mikko, Robyn, Tom, Jerry and Tyke reunite with Gam and Nibbles, and they follow Venom, Killer and the other Lugo Men, Cats, Dogs and Mice as they leave the hospital. Mikko and Tyke worries about Tomoko and Spike, two of the captives aboard the Lugo Warriors' truck. They all arrive at a deserted area, where Venom plans to dispose all the animals and humans. Catching them spying from the bushes, Venom captures, Robyn, Mikko, Tom, Jerry, Nibbles and Tyke and intents for them to suffer the same fate. But Silvar, noticing Mikko's smoke signal after helping Ito defeat some of the other Lugo Men, arrives to their rescue. She, Gam and Nibbles destroys Venom, Killer and their Lugo minions. All the victims, including Droopy, Dripple and their ally  Screwball Squirrel are all awakened.

On Rodak's spaceship, one of his subordinates reports to him about what has happened on Earth. Rodak orders Zandosis to cause a hurricane out at sea in order to show no mercy to Earth and its defenders. Back in Mount Olympian, Methusan creates a powerful weapon for Goldar to use against the monster: a metal box to absorb all of Zandosis' sound waves. He sents Magma and Silvar out to fight Zandosis, but forbids Gam and Nibbles to join in. As soon as Methusan went back to the inside of the cave, the rookie robot duo sneaks away to follow Magma and Silvar. While Gam, Magma and Silver distracts Zandosis, Nibbles returns to give Jerry, Tom and Robyn a ride to help the robots out. As the battle between the sea monster and the space robots continue, Zandosis fire his energy wave at Gam, but Silvar, who is carring the box passed to her by Magma, shielded her son and gets blasted in the process. Watching the fight from his spaceship, Rodak returns to Earth to aid Zandosis who was running out of energy. But before his master could get involved, Silvar force feeds Zandosis the box, and Gam and Nibbles hits it with their Heat Beam Rays, causing the box inside the monster's body to explode, destroying it from the inside and sending its remains to the sea. Angered by the death of his monster, Rodak swears to get Gam and Nibbles.