Issue 165 takes place in the aftermath of the head treasurer Hatamoto Asano is assassinated. Usagi and inspector Ishida piece together the clues left behind by the Black Goblin Gang and Nezumi the thief to lead them to meeting area between the boss of the Black Goblin Gang and the hidden Mastermind behind the whole operation. Usagi and inspector Ishida prepare to upcoming challenge of finding the stolen sliver and bringing the town justice for the previous murders committed by the Black Goblin Gang.
The conclusion of the Mouse Trap story arc wraps up the conflict between Usagi and inspector Ishida with the Black Goblin Gang in a intense sword fight. Drama unfolds within the Black Goblin Gang as the higher members are in a struggle for dominance over the gang. However, this is meaningless squabble to the true Master that controls the Black Goblin Gang and only waits for the a favorable outcome that helps his cause. Stan Sakai ends the Mouse Trap arc a showdown between Usagi and inspector Ishida against the Black Goblin Gang that will close the case on the missing sliver mint.