The Sasaki family is as elite as it gets, and one of its members, Tetsunosuke, has joined the Shinsengumi.  He would have joined the Mimawarigumi, a police force with pedigree, but he is considered a troublemaker, which is why he was sent to the Shinsengumi.  Kondo assigns Tetsu to Hijikata as an assistant, so Hijikata is forced to endure the new recruit...
We don't need this stain on 
the Sasaki family's honor.
No necesitamos que manche el 
honor de la familia Sasaki.
Não precisamos dessa mancha 
na honra da nossa família.