Seconding Higurashi though also mentioning that unless you have an aversion to reading, you should read the Visual Novel instead (especially if mind blowing is what you want, as it does that better... as well as everything else). If you do, though, the anime is okay I guess.
Summary:
A boy named Keiichi Maebara moves into a really small, out-in-the-country town named Hinamizawa. There, he meets 4 girls that he quickly becomes friends with, Mion Sonozaki, Rena Ryugu, Satoko Hojo, and Rika Furude. He joins their 'club' which is basically just an excuse for them to get together and play board games/other stuff, and generally has a good time. Then he discovers that Hinamizawa has a 'dark past' in that one person dies and another disappears each year on the night of the Watanagashi Festival... and starts to suspect that his new friends might be in on the mysterious past of the town.
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