Before he leaves for the school trip, Yoshiyuki is given a pendant by Sakura and told never to take it off. The trip itself starts with a boat ride and then a train ride to Nara, and Akane gives Koko a chance to sit with Yoshiyuki. He is tired because of the history lecture Otome gave him the previous night, though he doesn’t remember any of it and thinks that Koko probably knows more. She agrees to act as a guide and hopes to make some good memories, and the two then get teased by Wataru for acting like this is a honeymoon rather than a school trip. The first day of sightseeing has Yoshiyuki spending a lot of time with Wataru and the other guys though, and even when he does get some time alone with Koko while feeding the deer, he talks about how Minatsu likes animals too. This makes Koko have doubts about if they’re actually dating since she had thought that being lovers would be more special.
After a bath at the hotel that night, Akane and Anzu plan to sneak to the guys’ room with Koko, but the class representative Maya stops them. Fortunately, the guys had decided to visit the girls’ room and forcibly bring Yoshiyuki with them. Koko is happy to see him, but she gets embarrassed and slaps him after she accidentally drops all of her underwear in front of his face. Wataru then suggests some alone time for the couple, however it never happens because a Mu robot comes by the room first to bring someone a cell phone they had left in the bath. Maya doesn’t like robots and thinks that they’d be better without them, but this gets Yoshiyuki angry. When he questions what she has against robots, Maya angrily says that it has nothing to do with him and storms out of the room. The following day has the group visiting Houryuuji, and Yoshiyuki notices Maya giving him an angry glare when she sees him. Even when Koko takes him to see the large Buddha statue, Yoshiyuki’s thoughts remain on the Mu and why they can’t be respected even though they’re man-made like the statue is.
Yoshiyuki’s preoccupation with robots and Minatsu makes Koko feel lonely, and it doesn’t help either that he pays no attention when she shows him a set of deer figures she picked out at a gift shop. When they get back to the hotel, she asks to speak with him and suggests that they go to the Kasuga Shrine together tomorrow during their free time. She wants to write their names on heart-shaped ema because she believes it will allow them to stay together forever. Though initially surprised, Yoshiyuki agrees to go and pinky-swears it as a promise. His attitude, however, changes when he learns of something disturbing over the phone later from his sister.
So even on vacation, Koko gets neglected, and since they made it a point to pinky-swear for the promise to go to the shrine together, you just know that promise is going to get broken, especially considering Yoshiyuki looked so serious after whatever his sister told him over the phone at the end of the episode. It’s probably something about Minatsu since there’s been so much buildup with this robot storyline. If something happened to her, I could easily see Yoshiyuki rushing back home and leaving Koko behind. This episode served to emphasis how distant he can be to her (and how she still likes him regardless), and all this might very well be one of the main conflicts at the end of the series. The pendant that Sakura gave Yoshiyuki was also featured too prominently not to play a part, and I suspect that angle is how the magical sakura tree will come into play. Anyway, it’ll be interesting to see what will happen in these final four episodes, but I’d be surprised if they didn’t stick with a Koko ending.