DECEMBER HAD COME to San Francisco in fits and starts, like a visitor who wasn’t sure he wanted to stay. The skies were blue one minute and overcast the next; tourists overheated or shivered in their prepacked wardrobes, while residents traded sweaters for tank tops and back in a single afternoon. That’s normal around here. The Bay Area exists in a state of nearly constant spring, where the color of the hills—brown with a strong chance of brushfire in the summer, green and suffering from chronic mudslides in winter—is the only real difference between the seasons.

It was half past six in the morning, and the Safeway grocery store on Mission Street—never much of a happening nightspot, no matter how you wanted to slice it—was virtually deserted. The usual rush of drunks and club kiddies had passed through several hours before, and now all we had was an assortment of early risers, grave-shift workers, and homeless people looking for a warm place to spend the tail end of the night. By silent, mutual agreement, the homeless and I ignored each other. As long as I didn’t admit I could see them, I wouldn’t need to ask them to leave, and we both got to avoid the hassle.