Bleach

Terror! The Monster That Lurks Underground (13x30)

Air date: Feb 23, 2010

Nanao, Ikkaku and Yamada are all sent to investigate Soul Society's underground waterways following a string of thefts from the 4th Squad's barracks. Despite numerous booby traps the trio soon find the culprit. However, they also find a very dangerous Beast Sword as well.