It all begins when aliens invade and threaten to conquer the Earth! However, one member of the human race is chosen at random to duel the aliens and save the planet: Ataru Moroboshi, a lecherous slacker from Tomobiki High School who begrudgingly participates. All he has to do? Play a game of tag and catch Lum — the beautiful alien princess in a tiger-stripe bikini — by the horns. Unfortunately for Ataru, it’s not so simple, since Lum can fly and deliver electric shocks! Perseverance pays off, but once he catches her, Ataru experiences another shock: He’s now Lum’s betrothed “darling” and she isn’t going back to her home planet anytime soon!

(Source: Crunchyroll)