Girls' Last Tour, Vol. 4 (Girls' Last Tour, 4)

Chito and Yuuri board a train that runs below the forgotten remains of the streets above and take it to the end of the line. When they finally reach the surface of this new layer of battered city, they discover a mysterious creature that can learn human languages. With a new companion along for the ride, the girls' tour gets a little more lively-but what awaits them is beyond what they could ever imagine!