Kôsei Kimura

In 1604, Miyamoto Musashi attacked the Yoshioka family at their dojo and defeated master Seijūrō and his younger brother Denshichirō in two duels. To save their reputation, the Yoshioka family decides to fight back with all 100 family members and hire an additional 300 samurai. Now Musashi sets out to defeat all 400 enemies in his most famous battle.

A mother, a father and their child are in a dark box. The child is getting a cough constantly. The mother asks the father why we are getting such a strange situation. The father says he can't understand this situation. The bombing sound can be heard from far away. What is happening now?