This volume revolves around the time-traveling brother, what he did to come back to the “present” and the consequences of his actions. Now that the lives of the siblings have been explained and the reader knows about them well enough to get through the story, I think the series has backed away from explanations and is heading in a more action-packed plot. There are a few memories scattered throughout the story, but for the most part, everything centers around the evil, crazy, time agent people with giant heads.
The series is still massively violent (lots of bullets to the head), so I would say this is definitely for a mature audience–that hasn’t changed. This volume is definitely more interesting if you’re drawn in by an active plot. If you’re looking for answers about the family (like the details surrounding the death of that squid sibling), then this volume doesn’t offer too many details. It’s focus is on the time-traveler (one day I’ll remember their names).
If you enjoyed the first volume, then you’ll like this one too. I heard rumors that there will be a third volume, though I haven’t found any details about it. The series doesn’t feel finished, so here’s to hoping there’s a conclusion to everything coming to us soon!