"You were always a slave, Justine. You just couldn't see the chains."

Wes says Justine was always a slave: well, of course she was - she's named after one of de Sade's most famous characters, the heroine of The Misfortune of Virtue. In that, Justine is the virtuous sister of the debauched Juliette. For her virtue, Justine is punished, abused, made into a slave.

'Our' Justine, believed herself to be pursuing a virtuous course, avenging her sister Julia, but in the process she falls in love with the pain, with being subservient. Her relationship with Holtz is most definitely sado-masochistic: he beats her, she stays; he puts a knife through her hand, she stays; he betrays her, she stays so loyal she will kill him. With her master gone, she - somehow - becomes slave to another (Wes - who mentions knowing whose door to kick down to get answers which implies she stayed put, waiting to be found). She talks rebellion, goes so far as to pick up a wrench, yet he can control her with a few words, a promise of degredation ("do you want me to take your bucket away?"). Why doesn't she escape Wes? I mean, yeah, he's a hard bastard these days but she's a vicious little thug herself - she slit his throat last year, after all. So it has to be that she has become conditioned to being a slave, to maltreatment. Having Wes as your dominator is better than having no-one.

Wes: You were always a slave, Justine. You just couldn't see the chains.
Justine: Thanks, Swami, I'll meditate on that.
Wes: You think she would be disappointed?
Justine: Who?
Wes: Your sister. (Justine turns away) That's where it all began, isn't it? Sister murdered by a vampire, consumed by a need of revenge...
Justine, spinning to face him: For justice!

At the end of The Misfortune of Virtue, Justine has been reduced to a prisoner, condemned to die. Her sister, Juliette, who had followed a life of vice and eventually married a wealthy man, visits the prison and initially doesn't recognise Justine. Justine's virtue has led her to this, just as Angel's Justine has been led to her prison by her wish for justice.