Makoto Misumi and his followers travel to the Lorel Union in search of the mysterious mercenary company known as Picnic Rose Garden.

Their destination is the city of Kannaoi, home to the labyrinth where the mercenary company is said to have established its base. Along the way, however, they rescue a young girl named Iroha who is being attacked on a dark road.

At first, she seems to be nothing more than a runaway, but it soon becomes clear that she has ties to the prestigious Osakabe family of Lorel. Before they know it, Makoto and his companions find themselves caught up in a bitter family power struggle...