Wednesday, Feb. 16, 9:02 a.m.

As soon as I come up the escalator at the 16th Street BART plaza, the sun hits my face. At the top, Lonestar Swan, the gray-haired man memorialized on Clarion Alley, is feeding pigeons. The roar of the trains disappears and street noise takes over: car engines, horns and pigeons flapping their wings.

I am here, like the dozen or so others I see every day, to spend the morning — to stay put in a place where some 11,000 others pass through.

My office for the next three hours will be the southwestern plaza. My companions, the regular plaza residents, spill out from the half-dozen single-room occupancy hotels along Mission and 16th streets, or they push carts or carry luggage from somewhere else. No one wants to talk to a reporter, no one wants their picture taken, so I just stay and observe.

We can sit on one of eight purple benches on a plaza dominated by a circular iron railing designed along the lines of colored papel picado — cut decorative paper. I decide on a bench facing the BART entrance, next to the bus shelter on 16th Street.

9:13 a.m.

An old woman in a wheelchair wearing a ponytail and baggy clothing approaches from Mission Street. Her feet drag her wheelchair forward. She holds a cup of coffee in one hand and a root beer in the other as she maneuvers behind the bus shelter where the 22-Fillmore runs west on 16th Street. She is right behind me.

A man wearing a white hoodie approaches her. “What would you like?” he asks. “A cup of coffee,” she says, and he heads over to McDonald’s across the street and returns with two cups of coffee.

9:28 a.m.

Clouds slowly cover the sun and the temperature drops instantly. Behind me two middle-aged men exchange something. One of them is the man in the white hoodie. He hands a small package to a man dressed in black. The latter exchanges money for the packet and then disappears onto the 22-Fillmore.

9:35 a.m.

“That mother*$% is in jail ’cause that bi&*$,” says the woman in the wheelchair. She goes off about a friend behind bars, saying she’s “going to die,” and “Snitches die!”

9:40 a.m.

A man who looks about 60 years old approaches the group and leans on a post. He could be younger, because he wears baggy jeans and a Giants cap, but his wrinkles say he’s older. As the conversation winds down, the man in the white hoodie asks, “You wanna have some coke? You know what I’m sayin’ man!”

The 60-something murmurs something and heads south on Mission Street.

9:45 a.m.

He returns with four men in their 20s. The four stay near the Guatemalan food stand while the 60-something approaches the man with the white hoodie. I am clearly in the middle of whatever is going to happen, so I open my cell phone and pretend to talk to someone.

The five walk away from the plaza and head south on Mission. The man with the white hoodie follows, and all disappear behind the corner. The old woman in the wheelchair stays by herself.

By this time, hundreds of people have passed by, hardly looking at those who stay behind.

10:45 a.m.

A middle-aged woman holding three black carry-on bags approaches my bench and puts the bags next to me. She mumbles about hashish, then leaves the bags and wanders off asking for a cigarette around the plaza.

She gets one, lights up and stands 15 feet away, next to the decorative railing. The bags remain next to me as she smokes and talks to herself.

10:51 a.m.

A short man approaches her. He’s wearing an oversized leather jacket, a gray military hat and a sphere-shaped diamond ring. The man shows her two thumbed-sized plastic packages of powder in his left hand. The woman asks the man to move and they come toward me to stand on my left. Her carry-on bags remain unattended on my right as the ashes from her cigarette float toward my notebook.

10:53 a.m.

They continue talking as the woman unzips her jacket. They hug and the man puts his hands inside her jacket. After they embrace, the man no longer has the two small packages.

The woman asks the man to grab one of the suitcases next to me. The woman takes the other two and they both walk toward the 14-Mission and get on a bus heading south.

11:16 a.m.

Rain pours down unexpectedly, and dozens of people on the plaza run to seek shelter. I find a dry spot under the palm tree in front of me. The plaza empties as it continues to sprinkle.

11:40 a.m.

As soon as the rain stops, the dozens of plaza denizens return. I sit on the same bench. On the bench to my left sits a man wearing a hat, dark sunglasses, a leather jacket and a backpack. I look at him and he looks back at me.

11:55 a.m.

As the man continues to stare, I turn and notice an unattended piece of luggage. The full-sized blue bag was definitely not there before the rain and it’s unclear how I missed it getting there. People walking by don’t seem to mind it. It appears that unattended bags are hardly suspicious at the 16th Street plaza.

12:05 p.m.

A man with an unpleasant smell who carries his belongings inside a sleeping bag offers me two nickels. “You are a brother of color,” he says, explaining his kindness. “We are both minorities!” I respectfully refuse and he walks away, calling me a mother$*%.

12:10 p.m.

A shouting contest erupts between the woman in the wheelchair and another older-looking man. People going to and coming from BART hear the expletives but ignore them. The man retreats to the food stand on the other side of the plaza. The woman in the wheelchair makes it clear she wants him to leave.

The man and the woman stare at one another, and a Mexican standoff ensues. The plaza’s not big enough for both of them.

12:13 p.m.

A man wearing a purple beret approaches the man involved in the standoff. After they talk, they walk away. The old woman in the wheelchair wins. She sits in the place where she started out three hours earlier, between the bus shelter and the public restroom, watching the world go by.