James Wolk stars in "Zoo"

There's no denying that "Zoo" knows how to deliver a cliffhanger. The show's freshman season closed on a veritable wall of animals blocking the progress of our intrepid heroes, while the final moments of season 2 delivered a flash-forward that not only gave us a glimpse into the declining state of the world, but informed us that a major character we just saw killed (or so we thought!) is still, in fact, very much alive. See what season 3 has to offer when "Zoo" returns Thursday, June 29, on CBS.

Based on the bestselling novel by James Patterson (who's also an executive producer) and Michael Ledwidge, "Zoo" is a dramatic thriller about a worldwide wave of vicious attacks by animals against humans. James Wolk ("You Again," 2010) stars as zoologist Jackson Oz, who investigates the strange attacks alongside a team that includes Abraham Kenyatta (Nonso Anozie, "Game of Thrones"), a safari guide and friend of Jackson's; Mitch Morgan (Billy Burke, "Twilight," 2008), an oddball veterinary pathologist; and Jamie Campbell (Kristen Connolly, "House of Cards"), a journalist.  

As the series progresses, so does the ferocity and co-ordination of the animal attacks, making it quite plain that this is far from normal animal behavior. There's foul play at work, and it all gets very scientific, with mutations and triple helixes and genomic fossils and other terms I won't pretend to be familiar with.

Things appeared to be looking up in the season 2 finale: Jackson and Co. landed on a cure, and even got it out into the world. Unfortunately, another group of scientists was hard at work, too, and it wasn't interested in simply curing the animals -- its end game was to end the human race. The Shepherds, as they're known, work for Jackson's father, and released a gas that effectively sterilized all humans just as the animal cure was dispersed. Well shucks.

This is still the state of things in the season 2 epilog, which jaunts forward to the year 2027. The human population is petering out, with no babies born in the last decade, and Jackson works tirelessly to solve the problem of the ultra-savage razorbacks: unstoppable wolf-like hybrids that are another one of the Shepherds' charming creations, and which dragged off a self-sacrificing Mitch in the season finale.

We get a shot of proud poppa Abe with Dariela (Alyssa Diaz, "Army Wives"), who announced she was pregnant at the end of last season (before the gas was released). Their 10-year-old son is graduating from a grade school that will close its doors forever behind him, as he's among the last of the world's 10-year-olds. The whole thing has a very "Children of Men" vibe about it.

Outside the school, Abe is approached by a young blond woman who points out that the hybrid attacks are getting worse. Much more importantly, she tells him that the only person who can create a cure isn't dead, as Abe believes: It's Mitch Morgan, that solver of all problems and come-upper of all plans, and he's very much alive. This is his daughter, Clementine (Gracie Dzienny, "Chasing Life"), all grown up, and she knows where Mitch can be found. End credits.

Kristen Connolly as seen in "Zoo"

Like I said, "Zoo" knows how to keep us hanging. The show is taking on a notably different feel for season 3. What started out with an intriguing but not particularly complicated problem of "the animals are acting weird, what's up with that?" has moved into something much more broad. Presumably, season 3 will put a spotlight on Mitch: Where's he been holed up these past 10 years, and what's he been doing? How did he escape the pack of hybrids that, by all appearances, devoured him? Why has he been keeping his existence under wraps?

On a larger scale, season 3 examines what life is like in a world that has no long-term future. Even if Mitch, veterinary pathologist extraordinaire, comes up with a cure, as Clem says he can, we're looking at a society learning to recover from a 10-year gap in the population.

It also appears that the hybrids are this season's main overarching conflict, as is their creator, "a shadowy figure with a startling connection to the team's past," according to CBS. Said team is currently scattered to the four winds for the most part, but expect them to be reunited in the wake of the news that Mitch is alive, thus giving everyone a hope for the future.

Aside from Dzienny as the now-grown Clementine, there are a couple of other new cast members this season. Hilary Jardine ("Van Helsing") and Athena Karkanis ("Low Winter Sun") are set to appear in recurring roles in season 3. Karkanis plays Abigail, a gutsy operative with a surprising tie to Jackson, and Jardine plays Tessa, Jackson's new lady love who plays an important part in helping refugees to safety.

Catch the season 3 premiere of "Zoo" when the thrilling series returns Thursday, June 29, on CBS.