we are shown the root of syrin's drinking problem, then her complicated and bitter relationship with her uncle tom cassidy. really, you can't help but empathize with both of these broken people.
before this issue, black tom was just another generic baddie for me; now i can see the tragedy and the pain behind his character. and again, his relationship with cain is very touching. cain is facing a tough choice here: either he turns his best and only friend to the authorities, or he helplessly watches tom slowly wither away and die without a cure.
all in all, this issue can be read as a standalone story, i think.