When I started watching Charlotte all I know was that it was done by Kyoto Animation, and I like a lot of KyoAni's anime: Haruhi Suzumiya, K-On, Free, Angel Beats, Clannad, and A Silent Voice. I guess you could say I want into the series blind (Aside from the fact that I know KyoAni can do no wrong).
For the first five episodes of Charlotte, it seems like an episodic series. That is not the case. After episode six, you will realise that all episodes in the series are part of a single story arc. Also that Ayumi plays a bigger role in the series then you would guess from the first five episodes.