It seems that Hikari figured out that the sea village is pretty much doomed. Therefore, he does the obvious.
As for the sixth episode, I had mixed feelings about this for the fact that Hikari injured himself after redeeming himself. He apparently injures one of his toes while he attempted to swim, thus causing Chisaki to become upset over Manaka spilling the beans. To be honest, Chisaki wishing for summer lasting forever felt rather clichéd. Things are going to change no matter what, especially when they are adolescents. Eventually, they have to accept the end result even if it doesn’t work out.
On the other hand, I felt that Hikari’s character improved a bit more in the seventh episode. I think most of it has to do with him warming up to the people on the surface, especially after understanding Miuna’s situation. However, the conflict between the sea and land people during the meeting was rather childish for the former for the fact that they canceled the festival over some unresolved feelings. From this incident and forcing Akari to break up with her boyfriend (which didn’t happen), it only makes Hikari’s dad and the sea-god look like old and angry prejudiced people because they don’t care about Akari’s and Hikari ‘s feelings. Of course, we don’t know how his decision will affect Chisaki, but I think it’s a good thing that she admitted that change is bound to happen and that it can’t be stopped.
With Hikari and Akari decision to abandon the sea village, I wonder how it’s going to affect the others. To me, I don’t think it’s going to matter because friendship is more important than living in the sea. Sooner or later, the sea people are going to realize that this grudge against land people isn’t going to do them any good. I think it’s better to accept change rather than go against it since land people are humans! However, it makes me wonder what Hikari will do now since he abandoned the sea. Will he accept Manaka’s feelings and perhaps fall in love with another girl like Miuna? We’ll see as the sea people make their destruction, unless they accept change or some miracle happens.