It explains the families and the game of powers in Ergastulum, shows the origins and ranks of the Twilights (according to what has been shown until episode 9) and delineates the functions (and sometimes backstories) of almost all characters.
The only flaw of this special was the lack of a properly explanation of all the events from the latest episodes...
If your are having trouble with Gangsta's sometimes complicated plot, I recommend this. Don't watch it if you are ok with the plot; you may become bored.
