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...
I can't tell you what to do now 
that your family doesn't want you.
Ahora que tu familia no te quiere, 
no puedo decirte qué hacer.
Não posso te dizer agora o que fazer, 
já que sua família não te quer.