She's saying "then...!" as a way to express her expectant desire for something. I believe the way it is now gets the message across, but if someone can think of something better to put in, go for it.
If Mugi-nyan is anything like regular Mugi this is the last we'll be seeing of the wolf.
Are you not afraid of me?Nope! Not afraid!That's why I'm not scared at all!!And you, what is it you desire?*shake*Mio-nyan and Ritsu-nyan said that you were nice!Fuzzy wuzzy—I see.Is that so...Then!SHAKE!!*shake*Then... then... then!!*SNAP*