Early in the second season of “Manhattan,” William Petersen strides into the isolated New Mexico encampment housing the scientists at work on the first nuclear bomb. Petersen’s fantastic performance as the base’s new Army commander, Col. Emmett Darrow, instantly gives the show an injection of charisma, and it’s one of several elements that upgrades the sophomore season of the WGN America period drama.

Last year, “Manhattan” was generally pretty good or at least above average, but it took a while to establish consistent dramatic momentum, and it often felt overpopulated with underdeveloped characters. The bigger problem is that when viewers have hundreds of options in the scripted-drama realm, reasonable competence isn’t enough to ensure loyalty.

However, in the first four episodes of “Manhattan’s” second season, the atomic-age drama contains quite a bit of fruitful conflict and meaty character development, all of which amp up the show’s energy level and move it into much more compelling territory. Perhaps the best news about the second season is that it will consist of 10 episodes, down from 13 in Season 1. The meandering that cropped up in the first half of the first season is mostly gone, and the resulting tautness vibrates through the new season, as is only appropriate for a story that hinges on explosiveness. The sensitive direction of executive producer Thomas Schlamme, who bathes the New Mexico desert in a golden, bittersweet aura, also gives “Manhattan” consistent doses of both ambiguity and urgency.

Petersen isn’t the only new addition to the cast: One can only hope Neve Campbell, who makes very effective use of her limited screen time in early episodes, gets even more to do as the whipsmart, elegant wife of J. Robert Oppenheimer (who’s played with cool, haunted elusiveness by Daniel London). Mamie Gummer is typically engaging as a new member of the Women’s Army Corps, and Griffin Dunne has fun with his role as a booze-soaked reporter intrigued by the base’s many secrets.

Those secrets serve as “Manhattan’s” fuel, and judging by on-screen consumption, only copious quantities of alcohol can dampen the verbal explosions that threaten to blow up various relationships on the rickety base. It became clear over the course of the show’s first season that keeping enormous secrets, even from loved ones, took a huge emotional toll on the “Manhattan” scientists, who were also dogged by the terrifying notion that Germany’s teams might be much further ahead on their atomic work than the motley collection of geniuses in New Mexico.

Having an enormously important goal often galvanizes the scientists, despite their prickly egos, their arguments over competing theories and the lack of social graces that hinders many of them in social and professional situations. But in Season 2 especially, the potential price of failure looms over the entire base, which makes the constant presence of whiskey (and casual sex) easier to understand.

Darrow is bracing to watch in part because he experiences little doubt: The man appears sure that God has called him to increase America’s power by any means necessary, and if that means the United States needs a nuclear bomb, he’s ferociously committed to making sure the eggheads provide it. In his quiet but intimidating way, he rides herd on headstrong scientists like Charlie Isaacs (Ashley Zukerman), a young physicist who labors mightily to lead important scientific endeavors on the base, despite his relative youth, his troubled marriage and his moral qualms.

Zukerman ably portrays Isaacs’ frustrations as deadline pressures bring him close to cracking, and another standout, Harry Lloyd, deftly plays a British scientist whose arrogance and sarcasm shield a wounded heart. Katja Herbers displays nimble assurance as Helen Prins, one of the few female scientists in the bunch, and the dismissiveness Prins is treated with and the grit and humor she must constantly deploy certainly feel period-appropriate (and perhaps familiar to female scientists even now).

The admirable anchor of the show, however, has always been John Benjamin Hickey, who plays the brilliant and divisive scientist Frank Winter. His intelligence is exceeded only by his stubbornness, which landed him in hot water at the end of the show’s first season. Not to give away anything about Winter’s trajectory early in Season 2, but it’s a testament to the show’s strengths that even those episodes that don’t feature him prominently still work. That said, the installments that give Hickey scope to demonstrate his impressive range and finely calibrated intensity work very well indeed. Television has no shortage of male characters with large egos and conflicted hearts, but Hickey makes Winter’s flaws and his stoic endurance equally intriguing.

Olivia Williams is also terrific as Winter’s brilliant wife, Liza, who didn’t quite realize that moving to Los Alamos would amount to a prison sentence (getting off the Army base without hard-to-obtain permission requires extensive subterfuge). Williams is an actor of tremendous empathy and versatility; ideally Liza will get even more complex stories later in season two, some of which won’t necessarily revolve around her headstrong husband’s challenges.

TV Review: ‘Manhattan’ Season 2

(Series; WGN America, Tues. Oct. 13, 9 p.m.)

  • Production: Filmed in New Mexico by Lionsgate Television, Skydance Television and Tribune Studios.
  • Crew: <p class="p1"><span class="s1">Executive producers, Sam Shaw, Thomas Schlamme, Dustin Thomason, David Ellison, Dana Golberg, Marcy Ross; </span><span class="s1">director, Schlamme; writer, Shaw; camera, Richard Rutkowski; production designer, Ruth Ammon; music, Jeff Russo and Zoë Keating; casting, Jeanie Bacharach. <strong>70 MIN. </strong></span></p>
  • Cast: John Benjamin Hickey, Olivia Williams, William Petersen, Ashley Zukerman Rachel Brosnahan, Neve Campbell, Michael Chernus, Christopher Denham, Griffin Dunne, Mamie Gummer, Katja Herbers, Harry Lloyd, Daniel London, Daniel Stern, Richard Schiff.