They were laying low in Japan for a few months while Bats and company pretended that Gotham was a big safe city again.
They knew a few people who knew a few people who had been killed by a few people, and, eventually, they were in a polite Tokyo nightclub, talking to polite Tokyo yakuza, with Harl's stuttering tourist Japanese dueling with the soft soothing responses of a trained lawyer.
Joker leans over to the girl on the right, teenage thing with a schoolgirl uniform and a carefully protected sword and whispers "Wanna see a magic trick?"
Go-Go just smiles.
This Batman/Kill Bill story was written by Kate Bolin. If you liked it, there's plenty more at http://www.dymphna.net/fanfic/. And you can feedback her at dymphna@dymphna.net.