First, a pretty extensive summary of the miniseries: "Last Generation spirals out of the finale of Star Trek VI: The Undiscovered Country, in which an assassination plot threatens the historic Khitomer peace conference between the Federation and the Klingons, their homeworld now dying after an ecological disaster. In the movie, of course, Kirk derails the conspiracy just in time. In Last Generation, for reasons that become apparent later on, Kirk's rescue comes a moment too late; the conspiracy succeeds, the peace talks collapse, and the Federation and Klingons slide inexorably toward war. But, because the Klingons now find themselves in a battle for their very survival, they fight even more ferociously than ever before, leading to their eventual conquest of Earth.
The series itself begins seven decades after the failure at Khitomer; the Klingons now rule the planet, while Jean-Luc Picard champions a rebellion against them, struggling to liberate Earth. But for the Resistance, the situation has grown increasingly desperate-Worf, the Terran warlord, begins tightening his grip, and it's quickly becoming now-or-never, do-or-die. The rebellion's final hope lies in the computer brain of an android named Data, invented for the sole purpose of scrutinizing the Empire for weaknesses.
Instead of potential weaknesses, however, Data discovers a single, fundamental flaw underlying the entire foundation of Empire: It was never meant to conquer Earth. History has fractured, and the Empire, as it is now, was never meant to exist. When Picard recognizes that the cracks in the timeline all converge on Khitomer, he realizes that their only chance for survival has become to travel back to the past and repair the damage.
But this isn't as philosophically obvious as it sounds-the members of his Resistance have all lived inside the fist of the Empire's brutality for years, losing countless friends and family to unrepentant Klingon bloodlust. To some, the idea of changing time-even correctly-to transform their occupiers into trusted allies remains unthinkable, virtual madness.
So, with the Resistance racing against what may be its final days, Picard must contend with the splintering dissent that infects all guerrilla movements, holding his insurrection together by sheer force of personality, all while struggling against an overwhelmingly superior enemy and searching for a way to rethread history itself. It is, shall we say, not exactly a stroll through the vineyards."
On the characters: "in addition to alternate versions of Picard, Worf, and Data, you'll see a character from the Original Series, a character from Voyager, and a few other nifty surprises along the way. (A fan of "Yesterday's Enterprise"? You'll be happy here.) There's also a character who's only ever appeared in a Pocket Books novel". Plus an extensive role for Wesley Crusher apparently.
Harris reassures readers that despite all the timelines and time travel stuff hinted at he will not be utilising the "reset button" to wipe the story out of existence at it's conclusion
On the relationship between IDW and Pocket Books which led to the series falling under the Myriad Universes banner Harris commented that when he took on the Star Trek editing job he was sceptical about trying to tie to two companies work together, seeing it as limiting to be tied down to a whole other extended continuity. However as time went on he saw the light and started to forge a relationship with Pocket, starting with the New Frontier miniseries and continuing now in Myriad Universes.
Commenting on his successor as Trek editor, Andy Schmidt: "I think Andy's a stellar choice (no pun intended) for the Trek editor spot, a consummately skilled writer and editor who's extremely well-connected with high-level professionals in the industry. So I think we'll see some top-notch projects coming off his desk, whatever they may be". Harris notes that Schmidt has already indicated a greater effort to tie in with Pocket, and also notes IDW and Pocket have good relationship from shared projects on other franchises, so the future is bright for further collaborative efforts.
Read the full interview, at Trekweb.