Murcielago, Vol. 20

Kuroko's group goes to a hot spring deep in the mountains, where the
entirety of the
land is owned by the wealthy Yamatsukami family. But right as
the family is going to
decide the next heir, the third son is found
murdered... To make matters worse, the
only road in and out of the area is
suddenly destroyed! Cut off from the rest of the
world, the family begins to
whisper about a mysterious "Ayako." With little to go on,
how will Kuroko
solve this closed-room case?