The residents of the Los Alamos base camp receive a special visitor in this week's episode of Manh(a)ttan -- none other than Niels Bohr, he of the infamous model of the atom and one of the unquestioned giants of 20th century physics. Gossip abounds in advance of the great man's arrival, namely, speculation that the Danish physicist -- who has only just been smuggled out of Denmark by the Allies in the last few weeks -- will be replacing Robert Oppenheimer as head of the Manhattan Project.

High-profile visitors aside, much of this episode ("The Last Reasoning of Kings") focuses on Frank Winter and his seemingly fragile mental state, exploring just what drives this mercurial man to pursue his underdog bomb design so relentlessly, alienating pretty much everyone around him.

We open with a flashback to World War I, with soldiers huddling in a trench while being shelled by the opposition. The solders volunteer a young man nicknamed "Fathead" to venture out into No Man's Land to rifle the pockets of the fallen for documents, because he's the only one who's had any college. It's a risky endeavor: "What's your real name, in case you don't get back?" a fellow soldier asks. Cut to Frank Winter sitting bolt upright in bed in a cold sweat. That's right, he was the young soldier on the front lines, and clearly still suffers from a spot of PTSD -- hence his haunted demeanor, obsessive work ethic, and chronic insomnia.

Add to that the occasional waking hallucination from his WWI experiences. That insomnia is taking its toll. His mentor takes one look at him and says he once ran a study in college on sleep deprivation in rats. "Two weeks in, they looked better than you," he says. "Three weeks in they were dead." Alas, the army doctor refuses to prescribe any more sleep aids for him. Frank is currently viewed with great suspicion "on the hill" -- code for the Manhattan Project's on-site headquarters -- because of his increasingly erratic behavior.

Does Frank take his mentor's advice to go home and get some sleep? Do you really need to ask? He's keen to complete the next step in demonstrating his implosion bomb design, having just been given some detonation primers for another proof-of-principle experiment. If it works, he'll finally get his precious plutonium. While the test is officially scheduled for the following week, Frank insists it can't wait. Even though he's under constant military surveillance, he commandeers an MP, an army jeep, and one of his scientists, Paul Crosley (Harry Lloyd, nearly unrecognizable from his turn as the ill-fated Viserys Targaryen in Season 1 of Game of Thrones), and marches out into the New Mexico desert.

A confrontation between the two scientists is inevitable. Paul has been increasingly dismayed by Frank's behavior -- so much so that he asks Ackley to have him transferred to the Thin Man team. To Ackley's credit, he questions Paul's loyalty, observing that rats always flee a sinking ship. "Respectfully, passengers also flee," Paul counters. "To a worthy captain, I'm loyal to the end."

Charlie Isaacs has a meeting of his own: a brief sit-down with head honcho Robert Oppenheimer, who informs Charlie that he is pulling him from the Thin Man project. He will be assigned to shadow Bohr during his stay at the base. "We don't want him to stray," Oppie says. "You'll keep him on the straight and narrow and show him only our finest work, understand?" Translation: Don't let him anywhere near Frank Winter's group.

Charlie is not happy about being demoted to a glorified valet. Oppie responds by quoting Proverbs: "As iron sharpens iron, so one man sharpens another." Ackley has assured him that Charlie is "iron" enough to handle Bohr: "I hope he's right."

Iron might be the wrong material. The Danish physicist is eccentrically stubborn but in a far more fluid, less rigid way. For starters, Bohr refuses to ride in the town car waiting at the entrance gate, opting to take a leisurely walk instead, oblivious to the top brass welcoming party left hanging at his delay. Charlie tracks him down, and finds him puffing on a pipe while regaling a few rapt soldiers with a tale of "passing out in Germany and waking up in Britain" with the worst hangover of his life.

Side note: This is actually a true story. Bohr's harrowing escape from Nazi-occupied Denmark is legendary (for a full account, read Richard Rhodes' masterpiece, The Making of the Atomic Bomb), and he traveled to England via an unarmed bomber aircraft dubbed a "Mosquito," designed to fly at high speeds and high altitudes -- so high that passengers needed oxygen masks. Bohr apparently didn't hear the pilot tell him to switch on the oxygen and passed out. (The period of oxygen starvation probably did leave him with a wicked hangover.)

Eventually Charlie gets Bohr to Ackley's lab to "meet the Gadget" (the code name for the prototype bomb), entering to a standing ovation. Bohr is less than gracious: "Will you ask these engineers to leave?" Charlie points out that the men have prepared a detailed presentation on the bomb design for him, but Bohr explains, "After my dalliance with the Nazis, I don't relish the exuberance of crowds." Fair enough. Discussing the Thin Man design with Charlie, Bohr calls it the "last reasoning of kings," a reference to the French king Louis XIV, who had the phrase stamped on cannon.

The next stop on the tour is supposed to be the metallurgy lab, but Bohr ignores Charlie's direction and marches off in search of Frank's lab to view "the back-up plan." Charlie gives him the lowdown on the implosion design, his admiration for its elegance palpable: "The geometry, it's like a star swallowing itself." Bohr concurs that the design is impressive, but asks cryptically, "Do you think it is big enough?" That's when Oppie barges in, clearly displeased. Charlie is summarily relieved of his escort duties.

Out in the desert, Paul sets up a camera to record to the experiment while Frank attaches the detonators, to the great alarm of the soldier guarding them. "We don't have clearance to discharge explosives!" Frank says he'll take full responsibility and suggests he move the jeep a little further away from the blast zone. The big moment comes -- and nothing happens. Frank marches toward the blast site to check the connections. The apparatus detonates just as he approaches, the shock wave throwing him backward. True to form, despite the ringing in his ears and shrapnel cuts on his face, the first thing Frank says is, "How's the camera?" They need the photographic evidence that the test worked. Without it, there will be no plutonium for his group.

But then the jeep won't start, so Frank resolves to walk the 30 miles back to base. The soldier has orders to remain with any non-operating vehicle and tries to force Frank to stay at gunpoint. Frank's response is to invite him to shoot him point blank. The soldier hesitates and Frank disarms him, tucking the gun in his own pocket.

Paul Crosley gets stuck lugging the heavy camera, and registers his displeasure, telling Frank he's asked to be transferred to Thin Man to work with Ackley, a man who keeps "civilized" hours. Eventually he asks their soldier escort to maybe take a turn carrying the damn thing, but the MP refuses; he is shipping off to the Pacific the following week: "I'm done chaperoning the pencil necks I beat up in grade school." Paul is blase about the insult: "Brilliant. You'll be graduating from taxi driver to cannon fodder."

These two end up debating whether a single soldier can make a difference in a world war, as opposed to a team of scientists. It's kind of the Manh(a)ttan equivalent of two nerds arguing about whether Spiderman or the Flash would win in a fight. "If it weren't for guys like me, you'd be poking each other to death with sharpened sticks," Paul argues, since scientists gave the military guns, dynamite, radar, tanks, airplanes, and many other tools of modern warfare. "Without science, Patton couldn't have paddled a canoe because he didn't understand the laws of buoyancy." The MP doesn't buy it: "You think you need a PhD to float?" (Jen-Luc Piquant admittedly had the same thought.)

When they start wrestling over the canteen of water, Paul accidentally drops the camera, exposing the precious film, sending Frank into a rage. Paul pushes back, hard, telling Frank he is unfit for leadership, just a padded cell. Frank takes a deep breath, says that night is coming, and nobody is coming to save them. So they'd best push on.

Meanwhile, back at the base, Liza meets with the army doctor, pretending to need a sleep aid for her own insomnia. The doc runs her through the standard psychological questions about her mental fitness. Liza, to his surprise, answers with brutal honesty, giving us a glimpse of what she has sacrificed so that Frank can be on the Manhattan Project -- namely, a tenured position in the Ivy League and her own scientific research. "My husband's research is of vital interest to the government. Mine is expendable." Her marriage is struggling, plus she's not allowed to work on the base and has no idea why. "I barely recognize the woman I see looking back at me in the mirror." She gets the prescription, although the doctor isn't fooled. He tells her to make sure Frank doesn't take the pills with alcohol.

Liza doesn't fit in with the other women on base, the so called Ladies Auxiliary, who pay Abby a visit, Native American maids in tow, for an afternoon of gossip, booze, and mani-pedis. The ringleaders are Dot and Gladys, who are a lot like Hamlet's Rosencrantz and Guildenstern -- they're pretty much interchangeable in terms of petty voyeurism and casual racism. (Frustrated with one of the maids' inability to understand her instructions, Dot (or Gladys) gripes, "Two thousand years in this country, they still don't speak the language.") Liza's rebellious teenaged daughter Callie doesn't fit in either. Dunlavy catches her trying to escape from the base in the back of one of locals' trucks. Let's just say that despite some initial antagonism on her part, there was sparkage -- Dunlavy is a smitten kitten. And Callie seems to like the attention.

As night falls, our Trio of Bickering Misfits discover Frank has been walking all this way with a bit of shrapnel in the sole of his shoe. His foot is a bloody mess. As Paul bandages the wounds, Frank asks why he wants to work for Ackley, a man who punches a clock and keeps "banker's hours," while young men are fighting and dying on the front. He pulls the gun and points it at a terrified Paul, telling him that gut-level fear he's experiencing is exactly what it's like to be in the trenches: "There's no comfort in battle. And no one is coming to save us -- not Niels Bohr and not Reed Ackley."

Frank, Paul and the MP eventually do make it back to base. To Frank's surprise, Paul promptly starts packing up supplies again, telling Frank they can take his personal car back to the test site and re-do the experiment -- because he's pinched more detonation primers from Ackley's office. Paul is back on Team Winter, having decided he's a captain worth serving after all.

They missed the big banquet dinner in Bohr's honor back at the base. During dinner, Bohr accompanies Liza to the bar to refresh his drink, and when he asks after her own research, she confesses that her research had been on the sex life of flowers, but "here I'm just a physicist's wife." Bohr laments all the great minds forced to abandon their work because of the war, and tells her, "Flowers bloom everywhere, Dr. Winter -- even in the desert." We last see Liza meticulously making notes on a flower specimen in her notebook, having taken Bohr's words to heart.

At dinner's end, Oppenheimer tells the assembled dinner guests that the Danish physicist will be departing in the morning, laying to rest all the fevered speculation about a regime change and subsequent jockeying for position. It seems that Bohr's role in visiting the Manhattan Project all along has been to serve as a morale booster. When soldiers lose hope on the front, "They get pinup girls," Bohr tells Charlie when the young man follows him out of the dining hall. "You get a tired old man with a pipe."

And then Bohr reminds him of his prior question: "Is it big enough?" He meant whether it was big enough to truly serve as a deterrent to end all war. "Is it big enough that no sane person would ever dare to use it?" Charlie is honest enough to answer, "I don't know." But he pleads with Bohr to stay; the project could use his brilliance. Bohr replies that the human race seems to be hellbent on its own extermination, with an insatiable appetite for horror. "I've lost mine."

Like Frank, Bohr lived through World War I, and tells Charlie about a chemist he knew with an idea to weaponize artificial fertilizer. That was the last time scientists thought they could come up with a weapon so horrific, they could put an end to war, but instead, that chemist's legacy "is a fog of chlorine gas."

The chemist in question is Fritz Haber, a German scientist who pioneered a process for making synthesized ammonia, and its use in fertilizer had a huge impact on agriculture, combating famine around the world. Haber is also the one who suggested weaponizing chlorine gas, first used on April 22, 1915 at Ypres, killing 1000 French and Algerian soldiers in less than 10 minutes and wounding thousands more. (His wife, also a chemist, was so horrified by her husband's work that she committed suicide.) By the end of WWI, chlorine and other poison gases such as phosgene accounted for an estimated 90,000 deaths.

That's what happened to Frank Winter in the trenches during WWI. Being sent into No Man's Land saved his life. When he finally made it back to the trench after another intense round of shelling, he found all his fellow solders dead from poison gas. The final scene is the young Frank waking up in WWI hospital ward and pulling bandages off his eyes. A nurse joyfully tells him that the war is over and "There will never be another."

Putting a fictionalized Bohr front and center was a bit of a risk, but I thought the depiction was charming, even though the actual Bohr was likely very different. And I thought the starstruck young scientists being in awe of the great man was entirely believable. Physics has its celebrities, too.

It's always risky to depict real-life people in a fictionalized series (or a theatrical play, as with Michael Frayne's Copenhagen). That's one reason the creators of Manh(a)ttan have stressed repeatedly that -- Oppenheimer and now Bohr excepted -- there are no direct parallels between the characters on the series and real people. I think it's one of the series' greatest strengths, although hardcore history buffs probably can't help being annoyed by some of the liberties taken. It frees the writers to take the storyline to more interesting places, create conflict and situations that never happened (but could have), and really delve into the thematic issues that underpin the series. This was a superbly crafted episode, even without an explosive cliffhanger like the shooting of Sid Liao two weeks ago. Here's hoping Frank's team gets their plutonium next week.