"Urusei Yatsura" is a comedic science fiction anime series centered around the chaotic and often absurd relationship between Ataru Moroboshi, a lecherous and unlucky high school student, and Lum, a beautiful but temperamental alien princess from the Oni race. The story begins when Earth is threatened by an invasion from the Oni, who propose a game of tag to determine humanity's fate. Ataru is randomly chosen to represent Earth, and his opponent is Lum. Through a series of misunderstandings, Ataru wins the game by accidentally proposing to Lum, who takes his words seriously and becomes infatuated with him. This sets the stage for a series of comedic misadventures as Lum moves into Ataru's home, much to the dismay of his family and his childhood friend Shinobu, who harbors feelings for him.

The series unfolds in a largely episodic format, with each episode presenting new comedic scenarios involving Ataru, Lum, and their eccentric group of friends and acquaintances. Lum's presence attracts a variety of supernatural and alien characters to Earth, including her ex-fiancé Rei, a hot-headed and muscular Oni warrior, and Benten, a tough and street-smart alien girl. The cast also includes Ataru's classmates, such as the perpetually unlucky Mendo Shutaro, a wealthy and narcissistic rival, and Cherry, a Buddhist monk who often provides commentary on the chaos.

Themes of love, jealousy, and misunderstanding are prevalent throughout the series, as Ataru's flirtatious nature frequently leads to conflicts with Lum, who responds with electric shocks from her alien powers. Despite their tumultuous relationship, moments of genuine affection and loyalty between the two characters are occasionally revealed. The series blends slapstick humor, romantic tension, and science fiction elements, creating a unique and entertaining narrative that explores the absurdities of human and alien interactions.

"Urusei Yatsura" is notable for its vibrant and diverse cast of characters, each contributing to the series' comedic and often surreal tone. The episodic structure allows for a wide range of storylines, from lighthearted romantic misunderstandings to more fantastical adventures involving time travel, alternate dimensions, and alien technology. The series remains a classic example of early 1980s anime, combining humor, romance, and science fiction in a way that has influenced many subsequent works in the genre.