Kyousuke's grandpa has come to visit. He's brought some fresh fish and vegetables from the country since their grandmother doesn't think that they can get good food in the city. Kurumi is disappointed that he hasn't brought anything more interesting, so she goes rooting through his bag. She comes up with a rope. Grandpa wishes she had found anything but that. It's a magic rope that switches the spirits of the people touching the ends. The twins don't believe him, so he shows them by switching spirits with Kurumi.
Just then Kyousuke walks in, and they proceed to show him what the rope does. Kurumi wants to play with the rope, but Kyousuke doesn't have time for that (or trust her). He's going to the summer festival with Madoka and Hikaru this evening. He throws the rope back to Kurumi, but just then Jingoro jumps and knocks over the goldfish bowl. One end of the rope touches Kyousuke and the other the goldfish who falls out the window and into a passing cart. At home, Kyousuke flops around on the sofa like a fish out of water.
Kyousuke discovers that he's become a goldfish and finds himself in a large fish tank. He thinks this isn't all that bad but then realizes that he's in a goldfish catching tank at the festival. Who should show up there but Madoka and Hikaru. They were tired of waiting for Kyousuke and are passing the time this way. Hikaru comments that one of the goldfish looks like Darling. Madoka agrees, ``He can't decide which corner to go to,'' but Hikaru claims that it's because he's cute. She suggests a contest to see who can catch him, and Madoka agrees. Hikaru's net ends up breaking. Madoka's, ``Come here fishy fishy,'' leaves Kyousuke transfixed, even as a fish, so she catches him.
As they continue walking around the festival, Hikaru still wants the goldfish, so Madoka gives him to her. Kyousuke thinks that this isn't all bad, but he preferred it when Madoka had him. The twins run up, all out of breath. Kurumi almost spills the beans, but Manami makes up a quick excuse that Kyousuke has just caught a cold. He wanted to go goldfish catching with Madoka and Hikaru, so the twins are going to catch some for him.
The two rapidly catch all the red goldfish at the stall and bring them home. Unfortunately, none of these are Kyousuke; he's already home with Hikaru. She puts him in a glass in her room. The walls are completely covered with pictures of him, which he thinks is a bit much. At home Manami gets the idea that they can use Jingoro's sense of smell to find Kyousuke. He's been chasing the goldfish for so long, he's bound to remember how it smells.
Sure enough, Jingoro leads them to Hikaru's house. They teleport into her room, and find Kyousuke swimming in the glass. Jingoro immediately attacks the fish, knocking over the glass. The rope slips out of Kurumi's hands and hits both Jingoro and Kyousuke, switching their souls. Just then, they hear Hikaru's mom coming, so the twins grab the goldfish and teleport out, leaving Jingoro, who's really Kyousuke, to take the blame for everything.
Kyousuke the cat runs out of the house, chased by Hikaru's mom. As he's running away, he rounds a corner and runs smack into Madoka, making her drop the bottle of wine she was carrying. It shatters, spills all over him and hits him on the head; he passes out.
Back at home, Grandpa is commenting how unlucky Kyousuke is. First he was turned into a fish, and now a cat. Jingoro had been chased out by the time the twins returned, so they have no idea where he is.
Hikaru comes over to Madoka's house like she promised. Madoka answers the door carrying Jingoro. She explains to Hikaru how she found this cat, but says it's not Jingoro, ``It looks like him, but the color is completely different.'' Just then Kyousuke wakes up and is surprised, but happy, to find Madoka cradling him in her bosom. Hikaru asks for the cat, ``Because he's cute and looks like Darling.'' Kyousuke thinks that he's just fine where he is now, and Madoka isn't so sure about giving him up either.
Hikaru has the idea of letting the cat choose. They set him on the floor and both try to get him to come to them. The lines they use, such as, ``Kitty, come home with me and we'll sleep together,'' really floor Kyousuke. Of course, he has trouble deciding. Madoka comments that this is just like Kyousuke, but Hikaru say's she's just copying her; anyway the cat is like Darling because he's cute, not because he's indecisive.
Hikaru then goes and grabs the cat, saying, ``Everything that looks like Darling belongs to me.'' Madoka denies this, accuses her of cheating and, when she won't give in, turns around sadly, as if crying. This gets to Hikaru (and Kyousuke). She gives the cat to Madoka, who is instantly happy. When Hikaru accuses her of faking her tears and cheating too, Madoka says they're even. Kyousuke notices that Madoka really was a bit sad then.
Hikaru leaves Madoka with the cat. Hikaru called home and her mom was dead set against her bringing a cat home. Now that Hikaru is gone, Madoka gets ready for a bath. She turns on the water heater, and takes off her shirt and pants. This is a bit much for Kyousuke, who faints.
At home, Grandpa has set up a ritual to bring back Kyousuke's spirit. It involves the whole family, mystic symbols, chanting and clashing silverware.
Kyousuke wakes up, smelling something odd. The pilot light to the water heater has gone out, but the gas is still on; that's what he smelled. Madoka has gone to sleep on her desk. Kyousuke tries to jump up and turn off the gas, but he doesn't make it that high, slamming into the wall. He feels his spirit being pulled back (by the ritual). Realizing what will happen to Madoka if he doesn't help, he fights this and stays a cat. He hears Madoka talking in her sleep, ``Kasuga-kun, why did you have to get sick...''
He makes a great jump, but still doesn't reach the switch. However, falling from the wall, he bumps into Madoka. This wakes her up and she notices the gas. After turning off the gas and opening the window, she picks up Kyousuke. She thanks him for saving her life, and as a reward, gives him a kiss. However, just as she is about to, his spirit returns to his body. He comes to, kissing a very surprised Kurumi, who beats him up for trying this.
Kyousuke thinks that if his spirit had returned to his body just a few seconds later, he and Madoka would have kissed. The episode closes with Kyousuke again studying and thinking.