At lunchtime, when Yuu was eating together with Hime (pink-haired) and Eimu (blue-haired), having mustered her courage, Orie came to declare to him and asked him to go out with her.

This, of course, surprised and embarassed Yuu to the utmost point.

Confronted to his hesitation, Orie looked for advices in some book...

...and made her next move. "Since it'd be too early to go out together, let's go to a date first!"

"Just you and I?" replied a still surprised Yuu. This took Orie aback, so she had to consult once again her book... and gave her answer. "Let's make it a double-date!"

After all, it was too early for the two of them to be alone together, so she proposed her and Yuu go along with Eimu and Hime (which revealed Orie didn't fully understand the double-date part, but... ^^;;;;). Yuu, of course, accepted, putting Orie in a very happy but bewildered state. "Thanks a lot" she was able to babble...

...before falling unconscious, revealing her advice book was a dating manual.

So they all went together to the aquarium to spend quality time. Many things happened that day. When they came back, Yuu took Orie home and she told her about how she felt it was so natural for the two of them to be together, since it was the result of mutual choices and decisions they both took of their own free will.
The day after. The girls were reflecting about how Orie's confession didn't seem to have affected Yuu much.

As for him, Yuu was calmly but firmly walking inside the school buildings toward a certain destination. Then, having reached it, he said in a clear and firm tone: "Miss Natsuhara Orie, please go out with me. I do think as well that us being together is a natural thing, so let's go out". This left Orie just as much surprised as Yuu was previously

Speechless even.

But, blushing fully, she finally accepted.

And so, Yuu and Orie's romance took a new step!