Alien Warrior opens in space, and that’s the alien part out of the way. Our as-yet-unnamed protagonist (played by Brett Baxter Clark) learns from his father that his brother has been killed on a distant planet. Which, of course, is Earth. The father tells as-yet-unnamed that he must travel to this planet and defeat a Great Evil. You can hear in the dialogue that they capitalize it. Only then will as-yet-unnamed be worthy of being king (of what? irrelevant). As-yet-unnamed is warned that although they speak the same language on this planet, the people have very different thought processes.
As-yet-unnamed is transported to Earth. He arrives naked, but luckily a drunk homeless guy has some spare clothes to loan as-yet-unnamed. “My first friend,” says as-yet-unnamed. As-yet-unnamed stands in the street trying to ask questions of people in cars. Someone yells at him to get out of the street, buddy, and he adopts Buddy as his name.
One of the people who passes by is a crime lord (you can tell because we see him watch a drug deal go down). Buddy asks if the crime lord is a Great Evil, and the crime lord says “The Greatest,” as he drives off. This is about the extent of this movie’s Clever Foreshadowing ability.
Buddy watches martial arts practice through a window, and then uses his newfound martial arts knowledge to save a woman from being raped by a gang. And that’s the warrior part out of the way. The woman (Lora) runs an inner-city reading program, and provides a spot for Buddy to stay.
Buddy isn’t exactly telepathic, but he can tell when people are being truthful. He uses these powers to teach inner-city kids how to read, and give them confidence when adults insult them. He also punches a stop sign and builds a car from scrap metal. This convinces some of the local gangs to join up with him against the Great Evil. They go out and spray-paint graffiti like “Be Temperate” and “Do Unto Others As You Would Like To Be Treated.”
The Great Evil takes offense to these harsh “Sunday School” words. He sends some corrupt cops to arrest Buddy. With the help of a neighborhood kid that Buddy befriended, Buddy defeats the cops and drags them to their police chief, only to discover that the police chief is corrupt. Buddy is thrown into jail with a very large cash bond required. Lora is sad because she and Buddy have been falling in love.
The newly-temperate gang members decide to go and steal the cash bond from the Great Evil as he is in the middle of a drug deal and has a lot of cash on hand. They are successful at this, albeit with a lot of collateral damage, but further draw the Great Evil’s ire.
The Great Evil kidnaps Lora, and tells Buddy to meet him at the smelter (?!). Buddy shows up, and so do some of the surviving gang members. In the middle of the climactic fight, Buddy starts to phase out. He is being transported back to his home planet!
Lora will just have to save herself from the Great Evil with the help of the gang members. Back on his home planet, Buddy opines that time and death are an illusion; he and Lora will be together forever.