Nao’s arc ends when Sora goes from angry to depressed when she sees Nao give Haru mouth-to-mouth CPR after he almost drowns in the ocean. Sora ultimately tries to run away, but Nao finds her in the bus station. Sora spills her feelings out to Nao about being afraid of being forgotten by Haru when the bus station is hit by lightning, catching on fire with Sora’s stuffed bear in it. Nao risks her life to save the bear, as it’s Sora’s sole remaining memento of her mother, and this finally softens Sora up towards Nao.
As expected, Sora’s arc starts up where episode 8 started up, the difference being that Haru decides to tell Sora in episode 8, but is hesitant to in episode 10. Sora tries to use the fact that Haru doesn’t want to tell her about Nao to her advantage, sometimes working (in getting Haru to walk with her to school) and sometimes not (unable to prevent one of Haru’s dates with Nao). However, one night he catches Sora getting off…over him.
Well, I guess Nao’s arc ended about as well as cold be expected. It ended up Nao doing amazing for Sora that finally brought Sora around, and I guess it wasn’t anything too weird, though Nao and Sora were lucky not to get zapped by the lightning, just through the ground when it hit. Otherwise…there isn’t that much to say really. I think Nao saving Haru’s life perhaps started Sora coming around, but she was still too stubborn to go all the way until Nao saved her bear.
As for the start of Sora’s arc, Haru is obviously conflicted over Sora an his feelings for her, seeing his relationship with Nao as a way to finally get past his feelings, though Sora is doing everything she can to not make that easy. And I’m not sure what Haru was crying for at the end when he caught Sora. If he was crying over his guilt for his feelings for Sora or what. (that would be my guess).
I would say that finding out that Sora has those feelings for him, Haru is going to find it a lot more difficult to resist her temptations, though he was go through rejecting Sora almost completely first, before finally succumbing.