In 1993, the Oh My Goddess! (ああっ女神さまっ, Aa! Megami-sama!) OVA was produced by AIC, featuring the central characters of Kosuke Fujishima's popular Oh My Goddess! series. It was distributed in the US by AnimEigo. The storyline initially parallels the early parts of the original manga, and is similar to early episodes of the later 2005 TV series, but soon moves off onto a tangent of its own.

The story opens with Keiichi Morisato, a first year student of Nekomi Institute of Technology, left at home by his dormmates. While trying to order dinner, he accidentally dials the Goddess Relief Office, thus summoning the Goddess Belldandy, who offers to fulfil a single wish for him. Believing this to be a prank by his dormmates, Keiichi wishes for her to live with him forever. Keiichi is taken aback when Belldandy says his wish is granted, not least because women are forbidden from his dorm. Kicked out into the streets, and with a Goddess by his side, Keiichi takes his first step into a world he had never before even dreamed about.

Following his ejection from the dorm, Keiichi visits his other friends, seeking a place to spend the night, however, he is unable to find a suitable place to spend the night. To help him out, Belldandy directs Keiichi westward, though through overuse of her powers, she falls asleep en transit. Keiichi finds the abandoned temple, and carried Belldandy inside, though he also collapses soon after, due to an oncoming cold. He wakes the next morning to find that Belldandy has used her powers to restore the temple, thus providing them with a new home.

A few months pass, relatively uneventful, before Belldandy's older sister, Urd, decides to help advance Keiichi and Belldandy's relationship. Between the hints dropped by Megumi Morisato, Keiichi's younger sister, and Urd's advice, Keiichi finds himself at the beach, trying to make advances on Belldandy. Unfortunately, all of Urd's plans fail, usually through the interference of Sayoko Mishima. Ultimately, Urd gives Keiichi a love potion, however, it ends up backfiring, almost tearing Belldandy and Keiichi apart. All works out in the end, though Urd ends up banished from the Heavens for her interference.

Some time after this, Belldandy's younger sister Skuld leaves heaven, due to a combination of loneliness and frustration with work. Meanwhile, Keiichi has had the responsibilities of the NIT Motor Club forced onto himself, having to build a drag racing bike in time to ride it the following day. Skuld stumbles across this situation, and decides to try to make Keiichi lose, so that Belldandy would return to the Heavens with her, meanwhile Toshiyuki Aoshima is also trying to use this race to get Belldandy for himself, making a bet with Belldandy as the stakes. Partly due to Skuld's assistance, and indirectly by her interference, Keiichi is able to win the race.

A few months pass after Skuld began living in the temple when truly bizarre happenings begin to occur, the source of which being identified as bugs in Yggdrasil. Soon after, the cause of the bugs appearing on the mortal realm is identified as being the closeness between Keiichi and Belldandy, however, that is not the only factor. Skuld soon identifies that a huge energy is sealed in a nearby cherry tree, the source of which Belldandy seems to know, but is unwilling to say. At the same time, however, The Almighty has begun to move, and has ordered Belldandy return in three days time.

Recalling a promise to give Belldandy a ring, Keiichi chooses to use Belldandy's remaining days on Earth earning the money to buy it for her. Their separation is hard on both of them, but not as hard as being separated forever would be. Meanwhile, Urd and Skuld work together, trying to seal away the power in the tree. Ultimately, it is revealed that Belldandy and Keiichi had been friends as children, but as punishment for breaking Heaven's rules, Belldandy was made to seal Keiichi's memories. When they returned, the energy drawing the bugs into the mortal realm dissippated, and Belldandy was free to continue living with Keiichi.

From Wikipedia