With the help of Mutsunokami Yoshiyuki, Yagen Toushirou, Tonbokiri, Izuminokami and Saniwa head to the castle in pursuit of the Time Retrograde Army. Leading the charge, Mutsunokami witnesses the slaughter of the castle samurai at the hands of the Retrograde Army.

In order to find out the Time Retrograde Army's true purpose behind the castle attack, Izuminokami and company must stay in this era to continue their investigation.

Saniwa names Izuminokami Kanesada, Mutsunokami Yoshiyuki, Horikawa Kunihiro, Yagen Toushirou, and Tonbokiri as the Second Unit, and charges Izuminokami with leadership of the unit.