[kj1980]

Originally Posted by Rias

This epsiode made me think about the events in Watanagashi-hen...the fact that Shion can take Mion's place, without anyone noticing...makes me wonder about the events that happened at the last epsiode...

I wonder how Rena ties into this, after all, this arc is supposed to solve the Onikakushi-hen, no?

Read the English wikipedia article for Higurashi no Naku Koroni carefully:

Meakashi-hen (目明し編, Detective Chapter?), (Released December 30, 2004)
Answer to Watanagashi-hen. It is practically the same as Watanagashi-hen, however this story is told from a different person's perspective which allows the player to understand the mysteries of that chapter.

Note the word "practically the same" as well. It denotes a hint.