College freshman Morisato Keiichi gets more than he bargained for wen he goes dialing for dinner and gets an unexpected delivery - Belldandy, a real live, honest to goodness GODDESS! Belldandy grants him a wish, and Keiichi decides that what he really needs is a girlfriend just like her. And that's exactly what he gets. The mysterious Ultimate Force that enforces all Wish Contracts comes into play, and Keiichi and Belldandy are now inseparable. Then Keiichi remembers that his dorm has a strict rule: NO WOMEN ALLOWED!

Five months have passed since Morisato Keiichi dialed out for dinner and got a goddess instead, but he still hasn't managed to put the moves on the divine Belldandy. Belldandy's big sister Urd is not amused, and decides to give him some serious make-out advice. The result is a trip to the seashore, where every attempt by Keiichi to advance a base or two with Belldandy goes hilariously askew. Then Urd unleashes her ultimate weapon - the Love Potion!

It's really lonely up in the heavens without your big sisters to keep you company, especially when that means you are stuck with the job of tracking down all the bugs that keep cropping up in the Ultimate Force System. So little Skuld decides to pay her big sister Belldandy a visit. When she hears about the contract that binds Belldandy and Keiichi together, she decides that something must be done! Meanwhile, Keiichi gets stuck with representing the Auto Club in the University Drag Race, only to find out that his sempai, Tamiya, has a secret bet laid down on the outcome. But that's not his only problem. He's got an angry little goddess gunning for him!

Keiichi's life finally seems to be getting back to normal (or at least as normal as life gets when you live in a temple with 3 goddesses!). Yes, he does get strange dreams, and yes, Urd and Skuld are a pain, but what the heck - his girlfriend is truly divine! Alas, System Bugs are escaping from the Heavens, upsetting the balance of the Earthly Plane. Skuld gets on the case, and soon discovers that whenever Belldandy and Keiichi get close, a Bug Exhaust Port is formed. Until the problem is solved, Belldandy and Keiichi can't be together. Then Belldandy gets a Notice of Recall from the Lord. She has to go back to the Heavens, or else!

You'd think with a goddess as a girlfriend, Keiichi's life would be Heaven, but the fact is, it's coming to resemble the other after-life address. If he even gets close to Belldandy, Bugs escape onto the Earthly Plane and foul up the works. Worse, the Lord has slapped her with a Recall Notice. In two days, she has to relocate home to Heaven. As the clock ticks down, Belldandy must begin to erase herself from Keiichi's life and memory. And Keiichi? He's working his fingers to the bone so he can buy a ring for Belldandy. A ring that will fulfill a promise... a promise he doesn't remember making!