After all of the various trials and tribulations surrounding its creation, the Ojoshi is finally complete - cue celebrations from those responsible for crafting it, be they from the sea and the surface.
In fact, so proud are those involved that a stirring of a more fundamental desire springs forth - these kids want to use the fruit of their labours to resurrect the Ofunehiki festival that has otherwise been cancelled. It seems like nothing more than a pipe dream, but such is the determination and enthusiasm shown by those behind it that before we know it they're collecting signatures, convincing those in positions of power on both sides of the divide surrounding the festival, and ultimately arranging a meeting to talk things over.
With even Hikari's reticent father in attendance, hopes are high that the negotiations stemming from this meeting will be successful and bring about a reinstatement of the Ofunehiki, and this is only bolstered by the fact that all involved are decidedly impressed with the youngster's hard work and effort on the Ojoshi. However, when it comes down to the real crux of the matter, things soon take a turn for the worse - those representing the people of the sea expect an apology from those on the surface, and before we know it this group of so-called grown-ups are reduced to name calling and, ultimately, the threat of fisticuffs that eventually boils over into the inadvertent destruction of the Ojoshi. With Akari and her boyfriend also mired in the midst of this debate turned sour, things reach a seemingly impossible impasse while also destroying any chance of reconciliation between Akari and her father as she decides to leave to live on the surface. With Hikari also deciding to take his leave in light of his father's actions, things are looking decidedly depressing for Shioshishio.
With so much coming to a head here, this was a top-notch episode of Nagi no Nasukara - the instalment's heart-warming first half was perfectly offset by the harsh realities of the second in a world where the children are the ones acting like reasonable human beings while the grown-ups act like spoiled little kids. It isn't a particularly original sentiment, but it's one that never fails to resonate, and positioned in the midst of such heart-felt and engaging story beats it works rather well to create an emotional wave for the following episodes to hopefully ride on the crest of.