Belldandy unexpectedly gets drunk after drinking a can of cola and goes around Nekomi to spread joy to everyone and everything, while also causing Keiichi to experience extremely bad luck.
Summary
Chihiro hosts the Motor Club at a party at Whirlwind to celebrate the opening of her new shop, though she's celebrating slightly early as Keiichi and Belldandy are still busy hanging the sign up on the outside of the building. They enter inside and find Chihiro already drunk with a can of beer in her hand, and while she forces Keiichi to chug beer himself, Sora convinces Belldandy to sing for everyone.
Chihiro tells Keiichi that Belldandy is perfect, but she asks him if she wants to see her "lose it" by getting drunk. Keiichi turns down the offer, but Chihiro has Tamiya and Otaki restrain him while she gets Belldandy to have a drinking contest with her. However, Chihiro gives up after downing several shots while Belldandy is completely unphased by the alcohol. Later, Keiichi and Belldandy sit down and Keiichi hands her a can of Coca-Cola, as he couldn't find any tea for her. Belldandy sips the cola just as a drunk Sora wanders over and tries telling Keiichi how she's a woman despite being short and skinny, even attempting to show her bare chest to him to prove it.
Belldandy suddenly starts sobbing out of sympathy for Sora's plight, and Keiichi realizes that she had gotten drunk off the cola! She hugs Sora and declares that she gives her "all joy" and turns Sora turns into a giant with magic! Thankfully, everyone is too drunk to think too hard about what happened, but Keiichi realizes Belldandy had snuck outside and goes out to find her, though he trips and falls over a glass bottle.
Belldandy finds a stray kitten and feels bad that it has no home to return to, so she takes the kitten into her arms and teleports her to the Temple and right on top of Urd's head. Later, Keiichi's foot breaks through a concrete slab on the sidewalk and he steps in dirty drainage water. The next moment, he finds Belldandy talking to a little girl who lost her wallet. Keiichi tries stopping her, but a stray newspaper flies in his face and Belldandy summons a pile of wallets in front of the girl even though only one of them is hers.
Keiichi grabs Belldandy's hand and finds a pay phone to call Urd and explain what's happening. While she's also drunk and laughs at how Belldandy got plastered after one sip of cola, she tells Keiichi that his bad luck is due to the conservation of the law of happiness, meaning that whatever act of happiness Belldandy performs will cause unhappiness for him, since the System Force is still in effect. Keiichi then realizes that he's holding on to a dog's paw instead of Belldandy's hand and rushes to find her again.
Belldandy hears everyone in the local area complaining about their problems and gives all of them joy at once. She then finds a man at a fountain who finds her attractive and lies about having lost his girlfriend (she dumped him) and that Belldandy looks like her. He asks to be her lover for one night to heal his broken heart, but just as Keiichi arrives to intervene, Belldandy declines his offer, saying that she couldn't do anything to make Keiichi unhappy, even if it were to bring him joy. Undeterred, the man tries grabbing Belldandy's arm, but Keiichi calculates that he still has one unhappiness stored for use, and he waits for the fountain to explode in a plume of water.
As he runs off with Belldandy again, Keiichi feels afraid of what would happen if he were to let go of Belldandy's hand again, she would disappear, as not every dream can come true. As they stop above a bridge, Belldandy asks him if he's unhappy about something, and Keiichi answers that if he ever had to let go of her hand, he'd experienced the worst unhappiness imaginable. Belldandy tells Keiichi that she gives him all joy right before falling asleep from using too much magic, and Keiichi discovers that he is incapable of letting go of Belldandy's hand!
Once they arrive home, Urd tells Keiichi not to worry since as long as Belldandy didn't program it, they should be freed by tomorrow morning, though Skuld is already trying to pry the two of them apart.
Meanwhile, Sora is still a giant, and everyone at Whirlwind besides her and Chihiro have passed out on the floor.