Keiichi notices that Skuld has been acting strange lately, unaware that she has suddenly gotten a crush on him.
Summary
Keiichi secretly watches Skuld work on one of her inventions, but she seems disinterested and distracted by something. He brings it up with Urd, who contemplates if "that" has happened or not, but she doesn't mention it to Keiichi and offers to give Skuld an energy boost with a blunt syringe that's used for oiling machines. Keiichi flatly rejects the offer.
Keiichi believes that Skuld's behavior is just like when his sister Megumi had her first period, but he was unaware that goddesses could have that too. He goes to Belldandy to ask about it, but he's too embarrassed to say the word "period" to her and she has no idea what he's talking about. Despite the lack of an answer, Keiichi goes to a pharmacy to buy some things for Skuld, though he has to tell the owner that he didn't come for the "Happy Family Planning Kit".
Skuld realizes smaking one of her tiny robots look like Keiichi when he suddenly greets her from behind. She is confused by his "congratulations" for her and doesn't want the stuff he brought for her. Keiichi says he should've expected her to be irritable and now leaves her alone. Skuld finds that he left a package of sweet cakes for her out of a belief that they'd be better for her tummy and a package of soft, absorbent wipes whose purpose Skuld can't ascertain. Then, she takes out her tiny robot and makes it look more like Keiichi, which makes her remember when he told her he loved her at the Rock of the Three Sisters. She tells herself to stop thinking about him but gets flustered as she holds the robots in her arms.
Mini-Urd watches Skuld nearby and comments on what she sees as a fine mess. While she usually builds bridges between lovers, this time, she's going to break this one down, for both Belldandy and Skuld's sake.
Skuld later approaches Keiichi and asks him to take her around town so she can find all of the local parts shops. While her real goal is to prove that she hates Keiichi, she has a bad start when she's touched by Keiichi's kindness by giving her a motorcycle helmet for her safety. They depart on his motorcycle, unaware that Belldandy is watching them and is worried for Skuld.
Downtown, Keiichi and Skuld find themselves sandwiched in an unusually large crowd. This is thanks to interference from Urd, who used a spell to alter the vectors of human movement to make everyone bump into each other more in the hope of angering Skuld when Keiichi continually bumps into her. However, the spell is having the opposite effect on Skuld, who feels her heart pounding with how Keiichi is protecting her from getting bumped by strangers. Urd then attempts to triple the power of her spell, but it suddenly dissipates thanks to Belldandy, who wants Urd to leave Keiichi and Skuld alone.
At a tool shop, Skuld spots a set of wrenches that Keiichi offers to buy for her, but Mini-Urd swoops into his wallet and steals all his cash before he can pay for it. Thankfully, Mini-Belldandy secretly stuffs some money into his pants pocket just as he reaches there to check for it. Urd doesn't understand why Belldandy is trying to stop her, but she is determined to break Keiichi and Skuld up no matter what.
The rest of the day unfolds in a similar pattern until Keiichi tells Skuld that they need to return home. Suddenly, Skuld feels another beating of her heart and attempts to confess her feelings to Keiichi. Sensing what's about to happen, Urd turns to drastic measures and shoots the "Arrow of Lost Love" at them, which can break even the strongest heart with one shot. However, at the last moment, Belldandy appears and deflects the arrow with a forcefield.
Immediately, Skuld suspects that her weird feelings toward Keiichi were caused by Urd making fun of her. With light emanating from her hand, Skuld slaps her sister and leaves the word "baka" stuck on her face. Belldandy tells Skuld that when a goddess first comes into their magical power, they can become a little emotional and she suspected that it was her time. She congratulates her sister with a bouquet of flowers, and Skuld realizes that all of her feelings toward Keiichi are suddenly gone.
Leaving Skuld alone with Urd, Belldandy confides to Keiichi that she was slightly worried about what would've happened if Skuld had actually fallen in love with him, but Keiichi tells her not to worry about it because Skuld would never fall in love with him. Skuld agrees with Keiichi, and as she tosses the bouquet into the air, she says that she hates him forever!