Millions of overlapping, private Brooklyns make up the borough. They vary in almost every way people’s lives can; rich, poor, happy, sad, fulfilled, lonely, and all the Brooklyns in between.

The majority of residents glimpse, at most, dozens of these private realities. But a certain category of workers — plumbers, movers, and electricians, among others — see a far larger slice of the city. Frequently, they’re called in during moments of stress or transition. Often, they’re tasked with performing essential services people don’t like to talk, or even think, about.

Billy Swan, a life-long Brooklynite and long-serving member of this club, has been invited into thousands of versions of the borough. He’s surveyed meticulously remodeled brownstones, dilapidated basement apartments, a three-story townhouse owned by a hoarder, and an apartment where every surface was lined with crystal balls. He’s seen rich people arguing over money, adult children neglecting their aging parents, and lonely octogenarian bachelors yearning for conversation. He’s yelled at hapless 20-somethings, comforted new moms, and once, revived a woman who fainted in front of him. People hug him, argue with him, and send him photos. He gets lied to all the time.

The through lines are geography — and pests. A Brooklyn exterminator, Swan, 48, is sent to individual apartments and homes to handle roach, rodent, ant, fly, beetle, and bed bug infestations. While most visits give him a sense of who a resident is and how they live, bed bug calls, while not that frequent — they account for around five or six of the roughly 70 jobs he completes in a month — provide the most intimate and unvarnished windows.

Bed bugs were seemingly engineered in a lab to induce severe anxiety and revulsion. They’re mostly nocturnal, sucking our blood when we’re at our most defenseless. They feast in three to five day cycles yet can live for a year without feeding, which means that once you have them, you never know when they’re going to strike next. They invade our most personal spaces at a rapid clip, breeding in tight cycles with females laying up to six eggs a day.

In New York, where strangers exist in tight proximity and constant contact, bed bugs are a source of heightened concern. Live here long enough, and you’ll hear — or experience for yourself — variations of this particular genre of horror story, which often involve the insects’ stealth. Because their bites mimic those of mosquitoes, when they show up at all — around 30 percent of people aren’t allergic — victims can miss the problem for weeks. By the time a full-fledged infestation has bloomed, other distressing signs emerge: pillows and sheets riddled with black stains (from their feces) and red streaks (from blood-drunk bugs that have been crushed during the night), accompanied by the unsettling musty scent of their pheromones, which experts have likened to coriander.

These nightmare reveals are well-known in the city, as is the fact that bed bugs are savvy travelers, able to climb onto clothing, jump into purses, and lie in wait for a juicy host in movie theaters, bar lounges, the back of cabs, even changing rooms. If someone else has them, the consensus is: stay away. And if you have them, it’s a good idea to lay low and do your best to eradicate the problem without broadcasting to the world that you’re single-handedly feeding an army of parasites.

Add all of these elements together, and you get a recipe for extreme panic. Many of Swan’s jobs start like this: It’s the middle of the night, and somewhere in Brooklyn, someone has woken up to the sting of bites or, worse, a confirmed bug sighting. And so Swan’s phone rings. If he’s up, he answers. Part of this is financial — desperate calls usually translate into work — but it’s also human decency. After ten-plus years into the business, he knows that while he can’t do anything about the infestation itself, he can make the situation less terrible. Often, he gives the person at the other end of the line a task. Bag up the sheets and pillows, take a shower, put on clean pajamas, and go to sleep on the couch. When it’s two in the morning and you can’t sleep because you think something is sucking your blood, having a mission helps.

So does having someone on the phone who can credibly say: You will get through this. Here’s how.

“For the most part, once you start asking people questions they get away from hysteria and start making a game plan,” he said. “They just want you to tell them it’s going to be okay.”

If you live in Brooklyn and have searched for a bed bug exterminator online, chances are you’ll stumble on the Gowanus-based New York Pest Control, which has 23 reviews and an impressive-if-suspicious five stars on Yelp. Scan through the reviews, however, and you’ll see account after account from desperate, emotionally fried people profusely thanking the company for shepherding them through the ordeal.

Angela Balbi, who handles incoming calls, is regularly praised for her empathy. “Special thanks to Angela who not only set up the appointment with ease but managed to walk me off the ledge since this mess has been such a depressing and chaotic situation,” writes one user. “Without pushing any services on me, she listened to my story about mystery bites, and gave me thorough advice. I spent 20 minutes on the phone with her and she made me feel better than anyone I've talked to about my situation,” writes another.

As for Swan, he’s praised in virtually every review. Marcia (who declined to use her real name, citing fears it would damage her reputation as a landlord) discovered why back in May, when she realized the mosquito bites covering her lower back were not, in fact, mosquito bites.

“I kept reading about Billy, Billy, Billy,” she remembered. “I called and I specifically asked for Billy. I didn’t want anyone else coming to my house.”

When I visited Swan and Balbi at New York Pest Control’s office on a punishingly hot afternoon just before Labor Day, they play downed their role as stand-in therapists while acknowledging that bed bugs truly do mess with your mind. Having both experienced bed bugs personally, they empathize with the anxiety and irrationality experienced by their customers. (Three years after a minor bed bug problem, Balbi says she still checks her bed for signs of a return every night.)

Balbi, 44, is responsible for scheduling: “I’m the mob boss. I send him out, and he puts a hit on [the bugs],” Balbi joked from the doorway to the back office, in between calls.

She spent the last few days in constant communication with a self-described neurotic who was waiting for Swan to come and spray his apartment for a confirmed bed bug infestation. “I felt like I was dating him. I was waking up to text messages: ‘Good morning Angela!’” Balbi said. “I’m like, ‘Hey, how you doing?’ That’s how personal it gets. They’re dependent on us.”

Warm and instantly likeable, Balbi doesn’t mind the lack of boundaries; she answers texts as soon as possible, even on weekends. (Like Swan, she receives a lot of bite and bug photos to analyze.) Sprayings are staggered 14 days apart so that any unscathed eggs, which are protected by a layer of fat, have time to hatch but the resulting bugs don’t get a chance to lay eggs of their own. Treatment takes weeks, sometimes longer, which is ample time to form connections. “There was a bed bug job once where we got so close, we were both taking our daughters to a concert and we were going to meet up at the concert and have a drink together,” she said. “That’s how much time we spent on the phone.”

Usually, by the time Swan arrives, Balbi has managed to calm down even the most frenzied of customers. Still, he is frequently met at the door by people who are overwhelmed and sleep-deprived. His strategy is to immediately start asking questions. “If they are very upset, I’ll ask them about something in their house when I walk in. ‘Hey, where’d you get that?’ just change their thought,” he said. “And then you can talk to them.” Sometimes, his presence alone is enough.

“When a fireman rolls up, you smile,” he told me. “They believe that you are going to save them.”

“And he is,” Angela chimed in. “He’s never failed.”

Swan’s work brings him all over Brooklyn. For a time, he was a route exterminator — called mostly for maintenance jobs in large apartment complexes — but today, he’s more of a detective. When he enters, he does a sweep to assess the particulars of the case, before working with the customer to devise a plan of attack. He can spend multiple hours on one job; the majority of this time is typically spent answering questions and playing therapist.

It also exposes him to problems that extend far beyond pests. “I’ve called people bad children for the way they treat their elderly. I get crazy when I go into the house, I move the sheet and see 50 bed bugs. The daughter goes, ‘Oh I didn’t see nothing.’ That means you never change your mother’s sheets,” he said, getting worked up. Short and stocky with close-shaven hair, a neatly trimmed beard, and a thick New York accent, Swan is a charismatic, expressive talker who doesn’t mince words. “You don’t need to be a bug expert to know you are neglecting this lady,” he continued. “You see it all too often.”

Getting lied to is a regular part of the job. So are uncomfortable family dynamics, like when a woman in Connecticut called to arrange a bed bug appointment for her 24-year-old son. When Swan arrived, he’d failed to dismantle his bed frame or put his clothes in bags as instructed, which meant Swan couldn’t spray. He chewed the kid out and left, only to receive a second call from the mother. “She said, ‘Can I pay you to do all that? Just put my credit card and charge me for everything.’” Swan shook his head, amazed.

Couples fight in front of him all the time, and he’s witnessed first-hand how money doesn’t always buy happiness: “Rich people can be outright pricks to their families.” Many of his customers, particularly the elderly, are isolated and deeply lonely. “They just want to talk to you,” he said. Bob, a former customer in his seventies who Swan helped with a cockroach infestation, regularly calls to discuss theoretical plans of attack. “He likes to ask me about ‘maybes,’” Swan said. “‘What if one got into this cabinet?’ I go, ‘But Bob, it didn’t.’”

He encounters a rich variety of mental illness: people who are convinced there are bugs where there aren’t any, hoarders who only want him to spray in a particular area of the house, renters who have their own personal supplies of pesticides. Once a customer asked him if he could vacuum up the bed bugs instead of killing them, and then release them into Central Park.

But, by far, the most systematic problem he encounters is poverty — and its asshole cousin, gentrification.

It was a grey rainy morning in early September, and Swan was at a job in rapidly gentrifying Flatbush. This was his fifth or sixth visit, all at the bequest of a landlord, who owns two units in the building, one of which is about to be totally renovated, after which it will command a significantly higher price than what the old tenants paid.

There was just one problem (or, more accurately, many small ones): bed bugs were getting in from the other apartment, a rent-controlled one-bedroom that’s home to a family of five.

Swan has sprayed this apartment a handful of times over the past few years, but the infestation has never entirely gone away. The issue, he believes, is that the family is not following the proper protocol, which is extensive. It includes washing all bedding, linens, and clothing in hot water and then drying them; placing the items in garbage bags; vacuuming items that are not machine washable and putting them in sealed bins; unplugging all electronic devices; washing and vacuuming floors, carpets, moldings, electrical sockets, couches, and rugs; moving all objects away from the parameter of the room; and finally, taking apart the bed frame. “They’re maintaining.”

The landlord knocked, and a woman, holding a toddler, answered to let them in. Swan immediately spotted a bed bug crawling on the living room wall. There was a second one to its right. They were both about an eighth of an inch, which means they have a ways to grow. Baby bed bugs are the size of a pin, but expand with each feeding; well-fed adults are comparable in shape and size to plump apple seeds.

He sprayed them with rubbing alcohol. A young boy, armed with a plastic truck, watched gravely from the couch.

Swan moved into the bedroom, which faces the street. Rain streamed down outside. “Is it okay if I look through the sheets?” he asked. The woman nodded, and told him she hadn’t seen any bugs in the bedroom, just in the living room and a lone straggler in the bathroom. He raised the mattress; no sign of bugs. On the pillow cases, however, he finds blood and feces stains. “Maybe it’s pen stains?” the woman suggested. There are primary-colored scribbles on the walls. “They’re always drawing.” Swan told her he knows how it goes; he has five children. But these stains were definitely from bed bugs.

He asked if anyone sleeps in the living room. Sometimes, she told him. He searched the crib, and despite finding more blood stains, saw no evidence of the bugs themselves. The stains might have been from previous infestations. His theory was that the bugs are camped out in the living room, and feeding on whomever sleeps out there. If left alone, they’d eventually find their way back to the bedroom. He directed the information at the woman, but he’s also talking to the landlord, who stood by the doorway, tense.

Afterwards, Swan and the landlord went back to the empty apartment next door to strategize. Swan recommended opening the walls, and lining them with insecticide dust, which should kill the bugs if they attempted to cross through. He gets a lot of calls like this. Brooklyn is full of buildings where rent-stabilized apartments that go for $800 or $900 a month abut units that rent for thousands more. As a result, landlords regularly pay Swan for treatments out of pocket. “They don’t want to lose the $3,000 tenants,” he said.

But poverty makes following bed bug procedures difficult, even when the treatment is paid for. “There are so many times when you go into an apartment for bed bugs and you have four, six kids sleeping in one bedroom. Where do you put all their stuff?”

And when a treatment isn’t paid for, the cost can be prohibitive. An inspection through NYC Pest Control costs $100. A treatment, for a one-bedroom, starts at $875; each extra room is $75. These numbers run through Swan’s head all the time. He actively dissuades potential customers from having him come for an inspection unless he’s confident he’ll find something; otherwise, he advises they do a deep clean, and wait it out. If there’s a problem, signs will soon emerge. “It’s far from cheap, bed bugs. If I don’t find physical evidence, I’m going to feel like a crook to charge you for a job,” he said. “That’s what separates us from all the other companies.”

He takes pride in his refusal to overcharge or string anyone along for extra fees. Although official NYC Pest Control policy states that after a 30-day warranty, additional treatments cost extra, Swan mostly disregards it; if you’ve followed his instructions and the bugs are still coming from the same source, he’ll return on his own and spray for free.

“I always tell people on the phone, he takes it personal. He’ll come back as many times as he needs to come back,” Balbi said. “He will literally drive himself crazy if he can’t figure out what’s going on.”

Swan isn’t great with faces or remembering names; when he closes his eyes, however, he can recall the layouts of apartments he’s treated. “My family would tell you I don’t remember anything, but when it comes to jobs… I honestly take my work very serious.”

Months after the last bed bug sighting, Marcia said she still wakes up two to three times a night. She has redecorated her bedroom, removing the paintings and curtains, anything where bed bugs could hide. “It kind of changes you permanently.”

Marcia was adamant that she wouldn’t have gotten through the six-week ordeal, in which she was living out of bags, doing laundry every day, and sleeping almost never, without Swan and Balbi. “I was ready to have a nervous breakdown,” she said, and they were cognizant and respectful of that. Through texts and calls, Swan would reassure her that the infestation was temporary; an end was in sight. His extreme confidence in his ability to eradicate the problem was a lifeline. “That was the most helpful thing.”

Marcia said she confided in a few close friends, but as a general rule, bed bugs are designed to isolate. A cockroach or mouse sighting is an excuse to vent and commiserate. Bed bugs though? Try telling friends or coworkers you think you have them, and see how they react. What’s more, there can be legal repercussions.

Frank, a real-estate agent in his forties who declined to use his real name for exactly this reason, owns a unit in a co-op. Landlords are legally required to notify prospective tenants in writing about any bed bug outbreaks that have occurred in the building in the past year.

But Frank wasn’t sure what his obligation was as a shareholder. So after his wife woke up with bites and a dog inspection confirmed they had a minor infestation, he called Swan and asked him to come treat the apartment — in civilian clothes, so as not to alert the neighbors. (This, Swan said, is a frequent request.) The bed bugs are gone from his unit, but since then, they’ve been found in a few other apartments in the building. Similar discoveries are happening across Brooklyn, creating unacknowledged threads running through the borough that, unpleasant as they may be, tie us all together.