"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 and strong-willed alien princess from the Oni tribe. The story begins when Earth is threatened by an alien invasion led by the Oni, who propose a game of tag to determine humanity's fate. Ataru is randomly chosen to represent Earth and must touch Lum's horns within ten days to win. Despite his initial reluctance, Ataru succeeds, but his victory is misinterpreted when he accidentally proposes to Lum instead of his childhood friend, Shinobu Miyake. Lum, misunderstanding his intentions, falls in love with Ataru and moves in with him, leading to a series of comedic and surreal misadventures.

The series explores the daily lives of Ataru, Lum, and their eccentric circle of friends and acquaintances, blending slapstick humor, romantic tension, and supernatural elements. Lum's presence disrupts Ataru's life, as her alien technology and fiery temper often cause chaos. Despite his constant pursuit of other women, Ataru is frequently pulled back into Lum's orbit, creating a dynamic of love-hate interactions. Supporting characters include Shinobu, who harbors lingering feelings for Ataru; Mendou, a wealthy and arrogant classmate who competes with Ataru for Lum's affection; and Benten and Oyuki, Lum's alien friends who add to the series' comedic and fantastical tone.

The narrative is episodic, with each episode presenting self-contained stories that range from romantic misunderstandings to encounters with bizarre supernatural phenomena. The series incorporates elements of Japanese folklore, science fiction, and parody, often breaking the fourth wall and embracing absurdity. Themes of love, jealousy, and the clash between human and alien cultures are recurring motifs, but the tone remains lighthearted and whimsical throughout. "Urusei Yatsura" is notable for its blend of humor, imaginative storytelling, and memorable characters, making it a foundational work in the romantic comedy and science fiction genres within anime.