Indeed, from top to bottom, characters are coming into their own. In their off-duty moments, the chemistry sparks and sizzles between Moore and Sara, on the one hand, and between Kreizler and his mute maid, Mary, on the other. When Mary cuts her finger while preparing the doctor’s dinner, Kreizler notices the injury and slowly unwraps the bandage; the eroticism of the act is unmistakable even before he licks his own finger and applies his saliva to her wound as a “natural coagulant.”

Speaking of fingers, Sara’s later riff on why John would be a lousy typist is one big digit-based double entendre. “I think you lack dexterity — in your fingers, that is,” says. “All men do. That’s why they’ll never be any good at it.” I’m sorry, what were we talking about again?

Sex! Now that I have your attention, I reviewed last night’s episode of The Alienist for the New York Times. It was the best episode so far, by far.

Just when it seemed they’d cracked the case, it turns out the investigators on “The Alienist” don’t have a clue what’s really going on. Frankly, neither do I. Ain’t it grand?

With this week’s episode, “The Alienist” has reached the halfway mark of the season. It has also arrived at that most deliciously frustrating stage in any murder mystery: the point at which the detectives, fully armed with information and deductions, make their move, only to discover that they’re still several steps behind their quarry. For heroes and villains alike, this has the potential to be the most engaging and revealing moment in any such story. It can show us how the heroes deal with adversity and the villains with unexpected good fortune (if not so good for his hunters and victims). Lucky for us viewers, “The Alienist” is emerging from this stage of the race firing on all cylinders.

I reviewed this week’s fun episode of The Alienist for the New York Times.

Four episodes in, understanding what “The Alienist” does and doesn’t do well is a walk in the park. Well, it involves a walk in the park, at least.

The stroll in question is taken by Sarah Howard. Tasked by Commissioner Roosevelt with delivering John Moore’s purloined sketchbook to Dr. Lazlo Kreizler — whom she would otherwise as soon avoid, after his callous inquiries about her father’s suicide — Sarah finds the doctor people-watching in a local park. The person he’s watching, specifically, is a mother who once drowned her two young children in the bath. Protected from prosecution or institutionalization by her family fortune (sound familiar?), she now pushes an empty baby carriage around the park, doting on an infant only she can see.

Empathizing with such a person is a bridge too far, Sarah tells Kreizler. But the doctor points out that while the drive to kill may be alien to Miss Howard, the societal pressures faced by all women — “to marry, to have children, to smile when you feel incapable of smiling” — are as familiar to her as they are to the murderous mother.

“Society formed her,” he states bluntly, suggesting that everyone has the “raw materials” to become a killer, lacking only the external spark to make them “combustible.” It’s a provocative payoff to an exchange between Sarah and Kreizler earlier in the exchange, which seemed like simple black comedy at the time: Angry at the doctor for his attempts to glean insight into murder by probing her own psychology, Sarah sneers, “I don’t believe I have it in me to kill a child.” Kreizler smiles reassuringly and says, “You might surprise yourself,” as if he’s encouraging her to apply for a promotion or run a 5K.

If only “The Alienist” had the same faith in its audience’s ability to understand the complexities of its characters’ minds that Kreizler has in Sarah’s. Take the sequence in the park. It’s not for-the-ages dialogue, but the writing is certainly clear in its emotional and intellectual intent (Daniel Brühl and Dakota Fanning’s characteristically restrained performances make the gruesome details of their exchange even more memorable.) But the end of the sequence lays aside the scalpel and breaks out the sledgehammer: As Sarah contemplates Kreizler’s sad tale, children sing a schoolyard rhyme about putting a baby “in a bathtub to see if he could swim,” while a close-up practically immerses us in the waters of a nearby fountain. It could hardly be less subtle if the script had called for Ms. Fanning to turn to the camera and say, “Get it?”

I reviewed episode four of The Alienist for the New York Times.

“The Alienist” started its series premiere with a beat cop discovering a severed human hand. It began its second episode with an undertaker lighting torches fueled by decomposition gases in the bellies of corpses. This week the showrunner, Jakob Verbruggen, who is also the episode’s director, steers the series in a decidedly less disgusting direction, although the subject matter is no less disturbing: What is the etiquette for informing a high-society couple over lunch that their son may have murdered a young boy prostitute? Should one wait till after dessert, or just jump straight in?

Thomas Byrnes, the corrupt former chief of the New York Police Department (played by Ted Levine, who still bears the murderous imprimatur of his role as Buffalo Bill in “The Silence of the Lambs”), clearly feels his wealthy patrons the Van Bergens have no time to lose if they wish to keep secret their son’s possible involvement in the recent child slayings. The exchange is shot through with dark, absurdist humor by Byrnes’s hilariously long walks from one end of the Van Bergens’ lengthy dining table to the other. “Willem has got himself in water a bit hotter than usual,” he says to Willem’s mother, portrayed in a surprising, tight-laced cameo by Sean Young.

“Thought you should know now,” he adds, before hoofing it back to Mr. Van Bergen (Steven Pacey), who sits at the other end of the table, chewing a spoonful of pudding. “There’s no later.”

A comedy of manners? In a squalid period piece full of mutilated bodies? Yes, and thank goodness. Levine’s craggy deadpan, Young’s “well I never” fan-fluttering, and a second surprise cameo, from Grace Zabriskie as John Moore’s disapproving mother (Zabriskie played Sarah Palmer in “Twin Peaks”), temper the gloom and grime with charmingly effective humor. In Byrnes’s visit to the Van Bergens — which, by the way, gives us our first real hints as to the identity of the killer — and in moments like Mrs. Moore’s jumpy reaction to a ringing phone (“Oh! Loathsome machine!”), the writer Gina Gionfriddo gives us room to breathe after immersing us in so much horror and squalor.

I reviewed episode 3 of The Alienist, the best of the bunch so far, for the New York Times.

“The Alienist” does, however, play to the cheap seats in another way common to period dramas of its ilk: period-appropriate gore and squalor, and as much of it as you can stomach. The episode’s first shot is of a corpse, one of many laid out in a morgue and illuminated by flames lit to burn off the gas inside each cadaver’s bloated belly. A visit to the tenement home of the Santorellis, whose child was one of the victims, reveals a waterfall of sewage, a horde of screeching rats and a baby left to crawl through the hallway while the parents scream at each other inside.

Irish cops beat witnesses to a pulp. Underage sex workers in revealing drag attach themselves like leeches to prospective clients. The eyeless heads of slain humans and cattle stare blindly and balefully at us through the screen. The contrast with the opulence of the opera house and restaurant where Kreizler and his companions convene is striking, sure, but it’s also about as subtle as Captain Connor’s interrogation methods.

I reviewed episode two of The Alienist for the New York Times. This portion of the piece is mostly surrounded by stuff I thought was pretty decent, but I wanted to highlight this passage because man does this stuff get grating after a while. It’s so over the top that it makes it hard to take the rest seriously.