In an era of "peak TV," each TV critic has carved out a few passion projects — a short list of TV shows they believe are under-appreciated by both their peers and the TV audience as a whole. You probably don't need anyone to tell you to watch HBO's Game of Thrones or AMC's The Walking Dead; at this point, you know what they offer, and you've either opted in or opted out.

But it's harder and harder for new shows — no matter how excellent — to break into the cultural conversation. So allow me to state it as clearly as I can: If you care about good TV, you should be watching WGN America's Manhattan, which premieres its second season on Tuesday.

The "Manhattan" of Manhattan isn't New York; it's the Manhattan Project of the early 1940s, in which the government sent a group of scientists to Los Alamos, New Mexico, to develop the atomic bomb. Imagine a show in the vein of Mad Men — the rigorous examination of a bygone era, the deliberate pacing, the stacked ensemble cast, and, yes, the fashion and sex — except this time the stakes are saving the world, not landing a Coca-Cola account.

Manhattan stars John Benjamin Hickey as Frank Winter, a brilliant scientist hired by the U.S. government to develop a "gadget" — what we know better today as an atomic bomb. It's a project so top-secret that the vice president doesn't know about it, and Winter — a veteran who personally witnessed the horrors of chemical warfare in the trenches of World War I — passionately believes that his project, if successful, could mark the end of all wars, forever. He's also aware that a team of German scientists is working on the same idea, and that every moment he and his team waste is a moment that could give the Nazis the edge.

The development of the bomb makes up the backbone of Manhattan's story arc, but it's just one of many compelling plots in the series' ever-expanding narrative. Over the first season, we meet a rival team of scientists with their own competing ideas for developing the bomb; a cold-hearted interrogator (Richard Schiff) obsessed with ferreting out a mole he believes is selling U.S. secrets; and Frank's brilliant wife Liza (Olivia Williams), who gave up a career as a renowned botanist to support her husband's work.

It's hard to shake the sense that Manhattan's first season would have received infinitely more attention if it had premiered on AMC or HBO or FX. It has all the makings of a top-tier prestige drama — a statement of purpose, as The Sopranos was for HBO or as Mad Men was for AMC. It lacks just two things: respectable ratings and the attention of TV critics. On WGN America — a network that hadn't even attempted to crack the original drama market until 2014 — Manhattan faces a much more challenging uphill climb.

In theory, TV operates on an if-you-build-it-they-will-come model: Make a great TV show, and a loyal audience will find it (and proselytize its greatness to all their friends). In practice, that model is unreliable at best. For every Sopranos or Mad Men or Breaking Bad, which endured for seasons and ended on their own terms, we get a Deadwood or Firefly or Hannibal, good shows that have struggled to build an audience.

Fortunately, we also live in a TV era in which quality has never been placed at a higher premium. As audiences move toward streaming, seeking a deep roster of high-quality shows to binge on, networks are thinking about how best to build their archives — not just for the season, but for decades to come. In practice, that means bubble shows that would never have survived more ruthless times, like FX's The Americans and AMC's Halt and Catch Fire, have managed to stay alive despite a relatively tiny pack of viewers.

The same principle applies to Manhattan, which is creatively — if not financially — the biggest jewel in WGN America's crown. If it can find viewers, it's certainly good enough to keep them. (An exclusive streaming deal with Hulu, which offers the entire first season for its subscribers, should attract some new fans.) And as for the attention of critics — well, that's how I ended up in the middle of the desert in New Mexico, on the world's bumpiest bus ride, to see the set and meet the show's creative team in person, at WGN's expense.

Walking around the Manhattan set is as close as you can get to walking around 1943 Los Alamos. From the houses, to the cars, to the clothes, to the pots in the kitchen and the toys in a children's bedroom, every detail has been painstakingly realized. The show's creative team insists on painstaking historical accuracy — both for its own sake, and for helping the actors immerse themselves in the norms of the era. Manhattan is accurate down to "what proof of alcohol they consumed," says Hickey, or "how the wives washed their clothes," says Williams.

From the set | (Scott Meslow)

That level of detail makes it all the more surreal that Sam Shaw, Manhattan's creator and executive producer, didn't originally intend to make a period drama at all. "Six or seven years ago, I started writing something set in the present that was about the war on terror," he told me. But as he got deeper and deeper into his research, Shaw came to realize that he could best explore the far-reaching implications of America's global military presence by digging into the past. "The more that I read about the history of military secrets on this country, and this national security machine, the more it seemed to me that the story of the birth of the bomb was an origin story," he said. "A whole different culture of secrecy in this country was born. And we've been living in that world ever since."

The "culture of secrecy" is Manhattan's defining theme. "The enemy is looking…GUARD YOUR TALK!" reads a sign that dwarfs the houses in which the characters live. Checkpoints are rigorously enforced to ensure that the military knows where each civilian is at any given time. The protagonists operate under the correct assumption that every phone call is being monitored. Leaving Los Alamos requires permission from the colonel in charge of the base; outside letters are censored. And those working on the project are strictly forbidden to reveal what they're doing to anyone — including their spouses and children. "Everything is a secret! It's Kafka-esque!" complains Callie, the daughter of Frank Winter. "Well, at least she's reading," shrugs her mother.

As it turns out, that level of secrecy also extends to Manhattan's production; there are several things I saw on the set, and in the first few episodes of the second season, that I've been asked not to reveal. But I can say that Manhattan has doubled down on what worked about its superlative first season, with a series of twisty gambits that push the series into thrilling and unexpected territory.

There is, of course, a logical endpoint for this story: the atomic bombings of Hiroshima and Nagasaki. The first season began in 1943, roughly two years before the Trinity test on July 16, 1945, marked the beginning of the nuclear era, and every episode since has moved the story closer and closer to the end of World War II.

But Shaw wasn't worried about the series hitting an end-by date. "[Manhattan] presents itself as a story about World War II," he said. "But it's never really been about World War II. It's always been about what we became on the other side of World War II."

"The story is still going on," added executive producer Thomas Schlamme. "You can keep telling this story. The story about the creation of weaponry, and weapons of mass destruction. And who we are as a people. We're living it. Right now."