Repeated battles of high powered beings in Misaki City (in Tsukihime and its side stories) has caused stagnation and destroyed the balance of the land.
Haruna at Shin'i Headquarters hears of these events from her friend Akiha, the guardian of Misaki City. Mike, the talking-cat-boss-character, informs Haruka and her partner Takumi about the recent spree of murders, appearance of monsters and the most seriously the rumor about the towns turning into a "hallowed ground".They immediately leave to meet with Akiha and help her put an end to this nightmare.
Meanwhile Rin comes to Misaki City to search for the puppet master. Not knowing that she was about to meet with the rumored murderer she stumbles upon Nanaya... And gets helped by Haruna, whether she needed the help or not...
On top of all these Kohaku performs a summoning ritual to bring forth an ally to help in this dire time, as usual things go wrong and what she summoned turns out to be a girl called Sabre...
an extended description!