S1 • E1
Ataru has been randomly selected from Earth's population to face Lum Invader in a duel that will determine the Earth's fate./Lum's Stormtroopers summon Lum's UFO but instead get an intergalactic taxi that takes them through subspace. The fare for the taxi is the value of all the oil on the planet.
S1 • E2
A peach falls from the sky that Lum's cousin, Ten has travelled to her in. He is capable of breathing fire and fights with Ataru./Ten feeds his alien candy to a swallow, and made the swallow turn into a penguin-like creature. Each time an earth creature continues to eat alien candy, the creature will become a giant.
S1 • E3
Shinobu meets upon Rei, Lum's handsome ex-fiancé, and brings him to Ataru's house, much to the dismay of Lum./Ataru and his friends find Rei in a restaurant. His poor Japanese being mocked makes him go wild, and as he chases the boys and Lum throughout town, the chaos grows on.
S1 • E4
Kintaro appears with his bear companion. On an Earth field trip with his preschool, Kintaro shows the Earth kindergartners "the true way of living".
S1 • E5
The shrine priestess Sakura appears. Sakura ends up becoming Tomobiki High's school nurse, and all the boys in Ataru's class loose their collective minds.
S1 • E6
Lum, Ataru, and Shinobu's shenanigans destroy the town again. Ataru accidentally sets a small mirror demon free, and Cherry is called in to get rid of it.
S1 • E7
Ataru gets tired of all of Lum's electric shocks, so he gives Lum a special yellow ribbon specially made by Cherry to seal Lum's Oni powers. Later, Ataru walks in on Lum and Ten playing with space-voodoo dolls. It gives Ataru an idea.
S1 • E8
S1 • E9
The beautiful Crow princess Kurama is awakened by a kiss from Ataru. In accordance with her race's traditions, she must mate with him. Naturally Ataru is more than happy to oblige, but she wants absolutely nothing to do with him.
S1 • E10
Ataru's classmates encounter him and Lum at a Department Store downtown. After noting how inconsiderate Ataru is and how he seems more than happy to do so with Lum nearby, his classmates decide to exact some form of payback. Their plan includes sending Ataru a love letter with the intent to publicly humiliate him. Naturally, Ataru assumes the love-letter is legitimate, even though Lum angrily zaps him and wanders off. However, she soon overhears the classmates plan. At first, she is more than willing to let the plan happen to Ataru as a lesson...but then decides that she cares about Ataru too much. After subduing the girl who is part of the plan, Lum takes the girl's place and ruins the group's plan. Ataru is told about it afterwards, and at first feels upset that he owes Lum for saving him. However, his being upset turns to wonder as he suddenly realizes just how pretty Lum is, and they both walk together hand-in-hand in the falling Christmas Snow.
S1 • E11
Lum somehow ends up in the Heian period of Japan and now she must stop some ogres from the future before they kill Ataru's ancestor.
S1 • E12
Sakura invites Ataru and others at a local disco, which is a perfect setting for her boyfriend Tsubame. Kurama takes Ataru back in time in hope of teaching him to be her ideal man like her father.
S1 • E13
During a Hawaiian vacation at a beachside resort, the girls' swimsuits are stolen. Could Cherry be the culprit?
S1 • E14
Tomobiki High School gets a new student: Shutaro Mendo, the son of Japan's richest family. He and Ataru have a duel for presidency of the class.
S1 • E15
Lum takes Ataru to her home planet for the Setsubun Battle, but the game goes awry as he goes after the goddess Benten.
S1 • E16
In part 1, Ataru's brutal new homeroom teacher Kuribayashi has it in for him, and has a Lolita-complex thing for Lum. In part 2, it's Open House Day at Tomobiki High School, and a confrontation between the mothers of Lum and Mendou bring both planets to the brink of interstellar war.
S1 • E17
Mendo brings an antique camera to school that sends Ataru off into other worlds. - Ataru strangely becomes amazingly lucky to the point that Mendo loses his popularity.
S1 • E18
Lum's childhood friend Ran comes to Earth, but she's here to seek revenge on Lum for all times that Lum got her in trouble when they were both little. She also tries to suck out Ataru's youth by kissing him.
S1 • E19
Lum acquires Ataru's diary from the next day, which allows her to know what he shall go through today. Ataru tries to use it to his advantage, however.
S1 • E20
A fairy and her master put Ataru's class to sleep. While having a poetry contest the gang stumbles upon a strange woman.
S1 • E21
I'm "Duel. Ataru vs. Ataru" Ataru gets divided into 2 beings that are completely different. In "Walking to a Nightmare" Ataru goes to a deep sleep in class and his dreams make Mendo furious at Ataru and seconds away to kill him.
S1 • E22
Lum's father tricks Lum into coming home in order to hold a matchmaking ceremony for her, where thousands of alien suitors await her. Little did they know that Ataru has found out, and is on his way to the Oni homeworld to crash the party.
Lum
Ataru Moroboshi
Shinobu
Mendou
Megane
Cherry
Ten-chan
Chibi
Perm
Kakugari