That story was told in last week's Deathstroke #11: "Chicago." It's an old-school fill-in story which doesn't tie into any of the ongoing plots and stands on its own. The many spinning subplots in Deathstroke about Slade Wilson, his ex-wife, his daughter, his son and so forth are nowhere to be found. Instead Priest has taken this opportunity to consider the problem of gun violence in the USA. Artist Denys Cowan is an old Priest collaborator and inker Bill Sienkiewicz, a formidable and legendary penciler in his own right, enhances Cowan's art with his own style. Right here, this is top-drawer comics.
The plot of "Chicago" concerns the mothers of gun violence victims hiring Deathstroke to kill the gang members who killed their children. This draws in reporter Jack Ryder (aka the Creeper) who finds various aspects of the situation unusual - most notably that Deathstroke isn't using his guns to kill the gang members.
Priest isn't the only person to use Deathstroke as a means to comment upon gun violence as the recent Orlando nightclub shooting led to a DC benefit comic in which Deathstroke appeared to declare he wouldn't use guns any more, the kind of toothless cringeworthy but earnest reaction you expect from comics. (see the page here) Priest has no interest in having his Deathstroke adopt the moral high ground on the issue of gun violence - he is a mercenary who has always used guns and always will. When he is pressed in "Chicago" to suggest a solution to the USA's problem he offers: "Better aim."
This is also a comic book in which the Creeper appears, as the cover suggests. I'm certainly not up on what's been done with the character lately as Priest's Deathstroke is the first DC super hero book I've followed in many years, but Priest pays lip service to the evident changes others inflicted on the character: "I've been... going through some changes... don't understand them all... but I feel more like myself than I have in years!" Visually he's in his original Ditko visuals which, considering the tone of this book and the artists chosen, fits better than you'd expect. A bright yellow man with green hair and a red shawl can look a wee bit ridiculous, but Cowan & Sienkiewicz were game and made it work here. It also helps that the Creeper is held back until the climax. DC's recent "Rebirth" branding which brought Priest to his comic has seen many of the changes from "the New 52" walked back as many characters have been reverted back to their previous interpretations and that seems to be the idea behind Priest's take on the Creeper - whatever it was they tried to do to redevelop the character clearly didn't work, so here's the old version of the Creeper which still runs quite well.
Part of why Priest has had trouble with his artistic collaborators in the past is that he tells very complex stories with a great deal of text - which needs to be read - and visuals which need to be interpreted correctly. Sometimes he's instructed artists to plant clues to guide the reader towards the solution of a mystery he's creating, only for the artist to skip the clues just to get the page done. Priest needs collaborators who show up to work. And here we have Cowan & Sienkiewicz who most certainly have! The 1st page has 12 panels! I can't recall the last time I read a super hero comic with so many panels on one page! Their harsh, wild lines emphasize danger during the action scenes and while there aren't many characters in this story wearing colorful costumes, they run through a cast with dozens of different civilian characters who are each distinct from each other. I'd enjoy it if these two were the regular art team on Deathstroke, I'd love for Priest to craft more scripts tailored to their strengths.
Priest is, in real life, a priest, but he's never seemed too interested in using comics as a platform for sermons. "Chicago" offers no solutions to the matter of gun violence (Deathstroke does not throw his guns in a dumpster here). There is a killer who needs to be dealt with, but the big issues receive no closure, no "go and do likewise" no "visit this website and get involved." Priest has written about gang violence and tragic shootings a few times during his career and it's safe to say that even if he lives to write until the age of 100, he'll still have material to pull from our headlines.