BOSTON, JANUARY 23, 1 a.m. — Normally, the Pine Street Inn’s overnight Outreach Van — or OV — doesn’t venture behind the Boston Public Library. The van, one of two operated by the shelter, scours the city’s streets all night, every night, offering aid — transportation to a shelter for those who will take it, basic supplies for those who won’t — to Boston’s homeless community. The street behind the BPL, however, is off-limits.

According to Vinny Phillips, Pine Street’s acting outreach supervisor, he and his crew have been effectively barred from servicing the men and women who, on cold nights, seek warmth on the library’s large grates. The residents of an adjacent condo complex, he says, object to the OV visiting their block, on the grounds that it encourages homeless people to gather there — which, as it happens, suits the homeless people just fine. "They go behind the library because they know the vans don’t go there," says Phillips. "They don’t want us there."

Tonight, though, condo owners and grate dwellers alike will have to make an exception. With temperatures dipping close to zero, there is a very real chance that those who remain outside unattended until morning will not live to see it. Tonight, Phillips and his fellow outreach workers Shaughnessy Charbonneau and Jerry Davis are not taking any chances. "We just got a call from the Boston Police," Phillips says. "They want us to check on the folks behind the library." With this, the van swings right onto Clarendon Street and barrels through the abandoned city in the direction of the BPL.

It’s been a particularly terrible week for Boston’s homeless — and, for that matter, for the people who try to help them. For days on end, the city’s temperatures have barely edged above the mid-teens — dangerous conditions for those who live outside. Indeed, earlier in the week, a Korean War veteran named Bob Gurney perished a matter of feet from Pine Street’s Harrison Avenue headquarters. Although subsequent reports suggest that the 72-year-old died of natural causes and not from the cold, there is a sense of urgency among the shelter’s outreach staff, a sense that any slip could prove fatal.

"It’s hard," says Meghan Gaughan, a five-year veteran of Pine Street’s Daytime Outreach program. "You’ll leave someone and breathe a sigh of relief when you see them the next day. It can be very stressful."

Things tend to be even more stressful aboard the overnight OV, where life-and-death consequences can be more immediate. On the night I tag along with the team, oldies blare from the van’s radio and the three workers exchange plenty of banter, but there is an undercurrent of tension. "The fewer people we see tonight," says Phillips, gazing out of the window, "the better." So far, in the four hours since we pulled out of Pine Street’s parking lot, we’ve encountered a dozen or so men and women, none of whom has been interested in going to a shelter. As we pull up behind the BPL, it appears we may finally be in luck — the area looks deserted.

The spot the OV team is interested in, the steel grates that abut the library’s rear wall, is a mess: a snarl of rags, bags, newspapers, blankets. Scraps of paper and bits of cloth twitch in the warm air that rises from the grille, but there doesn’t appear to be anything actually alive here. This, it turns out, is just a trick of the eye. If you stare at the pile for long enough, a human shape becomes apparent amid the clutter, then another, then another — eight people in all, splayed out in various poses of stupefaction: elbows touching heads touching feet touching torsos — a people puzzle.

Weirdly, despite the skin-searing cold, the people on the grates appear to have kicked their blankets off. But this, we soon discover, isn’t the case. Every time we retrieve a blanket and throw it over someone, it forms a little hot-air balloon and wafts away. For 10 minutes or so, we grapple with this, using crates to hold the blankets down, tucking them under the dozing figures, who acknowledge our presence with an odd grunt or a wriggle. It’s an absurd, almost comical scene, the blankets billowing upward, the group of us silently going about the futile task of trying to keep them down. Eventually, we grab armfuls of the thicker blankets from the van, and these do better. Phillips, meanwhile, doesn’t even bother to ask the sleepers if they want to come with us. They are, he knows all too well, not going anywhere.