Iroha Tamaki was fighting a witch with her crossbow and when she finished she saw a girl staring at her and she recognized who it was and It was Nemu Hiiragi a girl who was friends with younger sister Ui and She was friends with a girl named Touka and Nemu approached Iroha.

“Sorry for this big sis..”

Nemu then uses her powers to knock Iroha out and then Iroha wakes up in a bedroom and there was pictures on the wall of Iroha Ui Touka and Nemu and Iroha’s legs were tied she could sit up on the bed but she couldn’t move far.

“You’re awake big sis..”

It was Nemu again.

“Me and Touka want you to join the Magius big sis..”

Nemu was very strict to some extent and calm since because Nemu is extremely smart.