I absolutely love these.

Ike's acquired a bunch of tickets to Misaki Waterland waterpark, and shares them with the class. Upon seeing the ticket, Yuji's face gets all 9_9. Shana is unsure of his facial expression, but it upsets her so she storms out of the room. She returns around lunch, having trekked to the next town to purchase some choice melon bread. Not wanting to be left out, Yoshida suggests they (Her, Yuji, Ike, and Shana) eat together.

Melon-bread wisdom

As they eat, another girl named Ogata-san walks by and suggests that they (including her) go to Misaki on Sunday. She wants to include Satou and Tanaka, but they refuse, saddening Ogata.
Later, it is revealed that Satou and Tanaka already had plans to take care of Margery.
Meanwhile, Ogata-san 'helps' Yoshida buy a swimsuit. And by help I mean she does a lot of teasing.
Yuji's mother has taken it upon herself to purchase Shana a swimsuit. Shana promptly begins putting it on, despite Yuji's presence. As a result, Yuji is violently thrown out of the room.

Beware flying Yuji's

The five meet at Misaki on Sunday, when a poster for a 'couple's calvary battle' catches their collective eye. It's a contest where the girl sits on the guy's shoulder, whoever wins gets a free gourmet dinner and bread. Yoshida-vision immediately kicks in, while Shana is more interested in the bread.

Yoshida-vision

After changing, the boys wait for the girls. They're pleased with Ogata's swimsuit, disappointed with Shana's, and again pleased with Yoshida's. A little too pleased.
An inevitable series of events has Margery wanting to go to Misaki Waterland, much to Satou and Tanaka's chagrin. It goes without saying they soon encounter Ogata-san, and she definitely has it in for them. After Shana ascertains that Margery is not up to trouble, the calvary battle begins.
The goal is to steal the headband of an opposing couple, the couple with the most headbands at the end winds. As luck would have it, Yoshida is paired with Yuji; while Tanaka is paired with Ogata, and Satou is paired with Shana. Tanaka suggests that fighting amongst each other is pointless - which is agreed to, up until most of the other contestants are eliminated. At this point, Shana becomes hellbent on going after Yuji, which causes both teams to lose their headbands, and causing a third party to win.

So spazzy

Where was Ike this whole time? Well, somehow he was coerced into babysitting Margery.

I love this line. 'What is this person?' xD

The end of the day has everyone parting, with Yoshida becoming increasingly worried about the fondness Shana and Yuji have for each other.

Thoughts:
Filler/fanservice much? That aside, Ogata-san seems to like either Satou or Tanaka, judging by the fact she flips out at them. I don't know if we even should care about her character, though. Yoshida, despite her initial happiness at being paired up with Yuji, begins despairing because Yuji and Shana are 'able to talk to each other so truthfully'. (Try as I might, I was unable to find a comprehensively appropriate English term for that.) If next episode is still fillerstory, I can imagine even more heart wrenching times for Yoshida.