Now, he was back and dressed like a gym rat. He wore a bulky black jacket to protect against the cold and the cap to shade his face from the cameras.

He kept walking to the next block, turned right and strolled the alley that surrounded the back of the DeSanto house. The same stone wall encased the rear of the place. The same spikes and two more cameras sat on top.

Mayburn sighed and kept walking. This was pointless. There seemed no way inside the damned house. He’d already contacted the neighbors of the DeSantos, the ones who lived on either side of them and two who lived across the street. He’d told them he was a lawyer who was moving to the city and looking for a house to rent. He wanted to see if they’d consider leasing their house. He’d hoped to take up residence and point a telescope at the DeSanto house, but no one took him up on this offer. They were all professionals with families who had no intention of moving anytime soon.

6. After seeing Jane, I started walking to the ‘L’ train, but I couldn’t stop studying everyone on the street, looking for a gray Honda, wondering if someone in another car was following me. Nervous, I flagged a cab and told the cab driver to take me to the Treasure Island grocery store at North and Wells, just a few blocks from my house. I grabbed a handbasket and headed for the produce aisle where I filled it with apples, pears and bananas.

I grabbed a plastic bag and started to drop kiwis into it when I realized that it was Sam who liked kiwis, not me. I’d been shopping for the two of us for so long, I’d stopped thinking what was Sam’s and what was mine. It was that way with everything in my life. I’d shared it all with Sam, and now it seemed impossible to separate it.

I was putting the kiwis back on the shelf when I noticed a guy lingering near me. He wore jeans, a long-sleeved black shirt and a quilted, army-green vest. He inspected some broccoli and put a couple stalks in a bag. He moved past, not even glancing at me.

But there he was again when I looked up from the tea selection. He was inspecting some coffee. And minutes later, when I was in the checkout line, there he was again two aisles over.

He’s only a guy in a grocery store, I told myself. Don’t get paranoid about everyone you see.

I left the store before the guy in the vest. I decided to walk down North Avenue, which was bright and packed with cars on a Friday night, everyone heading for happy hour or dinner with friends. Normally, Sam and I spent Fridays at home, recovering from work and making up for the sex we hadn’t had time for during the week. Sometimes we went to Bricks for pizza or Four Farthings for sandwiches, but we would soon be home, tucked in bed.

Now, I was on my way home to a dark, empty condo. I wondered whether this was the start of a new and lonely tradition.

7. John Mayburn awoke later than normal, thanks to the pre-birthday whiskey shots his buddy had insisted on buying him last night.

Tomorrow he would be forty-one, too old to be drinking shots in a bar on Lincoln Avenue, he knew, but sometimes it was easier to go along with his buddy, Mick, than to fight him. Also, there was something about those shots that for a tiny second made him remember being twenty-something in that same bar two decades ago. Back then, it had seemed the world was wide open and laid out in front of him. Sure, he was just an insurance analyst, a position he didn’t really love, and yes, his father’s friend had gotten him that job, but he was proud that he hadn’t followed his brother and sister into his dad’s leasing biz. He was proud that he was making a name for himself in an industry that had nothing to do with his family.

Now, he truly had made that name. As a P.I., he was as far away from the family business as you could get. And yet sometimes that place felt a little lonely, since he had no one, really, to consult with about his job. When he was in Wilmette with his family, he was envious of the camaraderie they shared, the way names of business associates and addresses of high-rise buildings were sprinkled into nearly every conversation.

They might all be in the kitchen for Christmas dinner, his mom handing out platters to be brought into the dining room. His brother, Peter, would hold up a dish of rice and sausage and say to his sister, Allison, “Can you imagine if Ethos got his hands on this?”

“Ethos,” Mayburn had learned, was Earnest Ethos, the owner of a number of downtown skyscrapers, with whom the Mayburns did business with.

“Oh, my God!” Allison would say, laughing, bouncing her youngest on her hip. “He would inhale it!”

Their father would come in then and make another comment about Earnest Ethos that would send the three of them into chuckles, while J.W. (his family never called him Mayburn) would slink quietly into the dining room with the plate of carved turkey.

He got out of bed now. He planned to put on a pair of jeans and head for his home office, like he did most mornings, but the whiskey shots were still causing discomfort. He grabbed a bottle of water from the fridge, chugged some down with a few of his vitamins and took the bottle back to bed with his BlackBerry.

He lay in bed, idly checking messages and e-mails, thinking that it wasn’t so bad to be almost forty-one and single. He could do whatever he wanted with his day, and he liked that.

The phone rang. He frowned at the screen and cleared his voice. “John Mayburn,” he answered in a pleasant voice.

8. The holiday season in Chicago is a beautiful thing. Sure, in January life will get bleak, and by February, most Chicagoans are suicidal, but in December it’s all good.

The three-story tree at Daley Plaza dwarfs the giant gold menorah by a hundred feet, and both of them tower over the little German village that gets set up below them. Michigan Avenue is ablaze in lights. The Salvation Army descends, and the clanging bells make it sound like Sunday morning all the time. El trains, decorated in gaudy fashion, speed by. The StreetWise vendors wear Santa hats at a jaunty angle.

The Walnut Room at the former Marshall Field’s is also a delight, and when Q said we should get some tea there, I took him up on his offer immediately.

I trudged after him up Washington Street. The sidewalks were lightly frosted with snow, and our shoes made crunching sounds.

We pushed through the revolving doors of Macy’s and walked through the gold and glass of the makeup counters. We took the elevator to the Walnut Room with its soaring ceilings, somber wood paneling and plush ruby carpeting.

Q ordered us a pot of English tea and two slices of Frango Mint pie.

We talked for a minute about some law-firm gossip. The waiter returned with our tea, and we watched in silence as he poured it into frail white china cups and left. Q fussed with his napkin. He sniffed at the pie. He spooned sugar into his tea.

“Okay,” I said, “that’s it. Tell me what in the hell is up.”

He gave me a guilty expression. “What?”

“You ordered Frango Mint pie? The most decadent dish in this city? And now you’re putting sugar in your tea? Q, I know you. You are always on a diet. So what’s wrong?”

Q pushed his tea away. “I’m thinking of leaving the firm.”

I exhaled loud and fast, as if I’d been suddenly pushed from behind. “You’re what?”

He nodded at my pie. “You eat. I’ll talk.”

I picked up my fork and cut off a bit of the Frango Mint. I chewed. The pie was smooth and minty and had the caress of dark, deep chocolate. But I was unable to enjoy it.