Sir Francis Drake was a busy four-lane divided road with shopping centers on either side, but there were also single-family homes and apartment buildings behind fences and hedges. A middle-aged man was pushing an old mower across a tiny lawn in front of a white bungalow. Trash barrels were lined up on a side street, where a yellow VW Bug pulled up to the intersection. I glimpsed the driver’s hands on the steering wheel. Four construction workers were sitting on a low concrete wall outside an apartment building, eating their lunches, their orange hard hats lined up beside them. None of these people knew what I was thinking as I drove past, and I felt sharply disconnected from them—from everything—as if I were in a parallel universe that mirrored this one but could not influence it.

According to the many-worlds theory of quantum mechanics, there is an infinite number of universes. They exist independently but in parallel to our own, so each of us may have an infinite number of replicas living in other universes. When I first learned this, I wondered if each version of myself lived exactly the same life, or if sometimes different versions made different decisions. And if one made a different decision, wouldn’t that set off a chain reaction of different decisions? Wouldn’t those different decisions transform us into different people? Or were we still the same person at heart?

“Twenty-One” started to play again.

At the next stoplight I made a U-turn.

—

Greenbrae Garden Center had a big parking lot that was about half full. I pulled into a space, switched off the engine, and sat there in silence, looking in the rearview mirror at the store’s entrance. People were coming and going, pushing carts full of flowers and tools.

It would probably be weird for me to show up at her work. I could back the car out and leave without anyone knowing. I didn’t want to seem desperate.

I checked my hair in the rearview mirror. I didn’t have any lip gloss with me, so I licked my lips.

I got out of the car and realized I was wearing my cutoffs again. I rolled up the bottoms, cuffing them high on my thighs. Looking at my dim reflection in the car window, I adjusted my tank top, and then I headed into the store.

I immediately saw the flaw in my unplanned visit: The place was huge. I passed spinning racks of seed packs, aisles of rakes and spades and ceramic pots, a carousel of gardening hats. The employees wore brown aprons with Greenbrae Garden Center printed on the front, but I didn’t see Steph anywhere.