Iroha Tamaki somehow after using up a lot of magic in a fight with a witch had passed out and used her Doppel which was just a manifestation of her own witch powers but she wasn’t really a witch so she could return back into her magical girl outfit however she was in a strange bedroom and looks around and she sees her younger sister Ui.

“Big sis..”

Ui then hugs Iroha, however this was Ui but it wasn’t at the same time because Ui had became a witch named embryo eve and somehow Iroha was able to still see Ui mainly because Iroha was trapped inside of her own Doppel.