Bleach: Season 1, Episode 170

1 - 170: Desperate Struggle Under the Moonlit Night, the Mysterious Assassin and Zanpakutō

Lurichiyo`s group is attacked in the middle of the night by an assasin and it`s up to Ichigo to defeat him. After the death of the assasin everyone is told that Lurichiyo is the heir to one of The Four Noble Houses. That is why Komui, the one that is trying to take over Lurichiyo`s clan, is sending his best assasin`s after them.