For a show that started its life in orbit, “The 100” clearly isn’t content just to go around in circles. In fact, this CW sci-fi drama earns points strictly for forward momentum, launching into its second season featuring a fast-evolving narrative, with the space-faring human population returning to Earth and facing a new set of problems. Not everything works, and the performances remain a trifle uneven. But with so many post-apocalyptic cliches being juggled simultaneously, it’s certainly a watchable and ambitious undertaking, albeit one whose main job will be to defy gravity by not yielding too much of “Arrow’s” lead-in.

Just to recap, nearly 100 years after nuclear near-annihilation, thousands of survivors have stayed alive aboard the Ark, a collection of linked-together space stations. But with the system failing, those in charge first decided to jettison 100 youthful prisoners down to the planet’s surface (hence the name), testing its viability before risking a full-scale re-colonization.

Season two begins with the Ark having sent the rest of its inhabitants back to solid ground, which is now teeming with disparate groups of survivors, most instantly recognizable to anyone who has consumed more than a dollop of science fiction. They range from scarred, primitive brutes nicknamed “Grounders” who occupy the Eden-like setting (OK, Vancouver) to a seemingly idyllic haven of refined survivors beneath the surface, led by a president (Raymond J. Barry) who gives off a creepy vibe despite his reassuring words.

“The 100” (whose numbers have been whittled down a bit, it should be noted) are pretty much scattered in every direction, with the capable Clarke (Eliza Taylor) skeptically joining giddy compatriots in the subterranean refuge, while others face more visceral environs above.

Meanwhile, Clarke’s authority-flouting scientist mom (Paige Turco) and the chancellor (Henry Ian Cusick, closer now to his “Lost” predicament, story-wise) keep butting heads over what’s best for the group, and specifically how to approach the former convicts now that they’re reunited in an ongoing battle for survival.

Adapted from Kass Morgan’s book, this Alloy Entertainment property draws from so many sources it’s scarcely worth citing them, though there’s an obvious desire to appeal to the “Hunger Games” crowd, while asking the question of what a repopulated Earth might look like if the gene pool was drawn almost entirely from models in Calvin Klein ads, albeit accessorized with a bit of mud and blood.

Still, the fast pace, multiple plot lines and life-or-death scenarios — coupled with solid anchoring from Turco, Cusick and Isaiah Washington — generally compensate for the show’s clunkier aspects and occasionally silly-sounding dialogue. And if that’s not worthy of a perfect score, give “The 100” extra credit for elevating its and the CW’s game above the remedial quadrants of the young-adult universe.

TV Review: CW’s ‘The 100,’ Season Two

(Series; CW, Wed. Oct. 22, 9 p.m.)

  • Production: Filmed in Vancouver by Alloy Entertainment in association with CBS Television Studios and Warner Bros. Television.
  • Crew: Executive producers, Jason Rothenberg, Leslie Morgenstein, Gina Girolamo, Cheryl Dolins; co-executive producers, Bruce Miller, Charlie Craig, James Thorpe, Michael Angeli; supervising producer, Dean White; producers, Aaron Ginsburg, Wade McIntyre, Tim Scanlan, Jae Marchant; director, White; writer, Rothenberg; based on the book by Kass Morgan; camera, Michael Blundell; production designer, James Philpott; editor, Hunter M. Via; music, Evan Frankfort, Marc “Doc” Dauer, Liz Phair; casting, Barbara Fiorentino, Danielle Auflero, Amber Horn. <strong>60 MIN.</strong>
  • Cast: Eliza Taylor, Thomas McDonell, Bob Morley, Marie Avgeropoulos, Devon Bostick, Christopher Larkin, Paige Turco, Isaiah Washington, Henry Ian Cusick