Next Izabel found the sandwich-maker Cami had mentioned in her dream. She knew right away he wasn’t the killer. He was an older man, with a broad build. She ordered a grilled portabello sandwich. And because he wasn’t the killer, she took her time watching how he cut the bun, how he shuffled along the counter, watching all the ways his body moved, all the ways that the killer’s body did not.

As she ate her sandwich, she opened her News app, still set to 2017, About the Air.

What are Spare the Air days?

Air quality in the Bay Area can be unhealthy at times throughout the year.

Spare the Air Alerts are called when ozone pollution is forecast to reach unhealthy levels. Ozone, or smog, can cause throat irritation, congestion, chest pain, trigger asthma, inflame the lining of the lungs and worsen bronchitis and emphysema. Long-term exposure to ozone can reduce lung function. Ozone pollution is particularly harmful to young children, seniors and those with respiratory and heart conditions.

When a Spare the Air Alert is called, outdoor exercise should be done only in the early morning hours when ozone concentrations are lower. Residents are encouraged to reduce air pollution every day by rethinking their commute and avoiding driving alone. . . .

The Bay Area Air Quality Management District is the regional agency responsible for protecting air quality in the Bay Area. For more information about Spare the Air, visit www.sparetheair.org.

The Air Quality Management District sounded like it could be a place for people to live in the sky. Izabel wondered how high they would need to go to be outside of the pollen’s reach. She imagined the thin air making her tired. She imagined coughing up blood into the snow. But they would need to go higher than mountaintops. She’d heard rumors that people were still living on space stations. She didn’t know much about that. People hardly talked about space anymore. She missed that kind of human ambition.

Where Izabel returned her tray, there was a new poster up. A Norwegian troll. Under it was written guardian of corpse-fjord, swallower of heaven’s wheel. When Izabel imagined swallowing heaven’s wheel, she could feel it large in her throat.

Jana came up behind her and Izabel jumped.

“Sorry,” Jana said.

“No, it’s fine,” Izabel said. “How’d tutoring go?”

“Good,” Jana said.

“It will work? To keep going to her?”

“Yeah.”

“And we can work on other things, too,” Izabel said.

“I know,” Jana said.

“Are you hungry?”

“No, I’m good. Kaito packed me a lunch.”

“Really?”

Jana nodded. “I ate it in the car.”

“Okay. Let’s go shopping then,” Izabel said.

Jana smiled but didn’t move. “Will someone recognize me?” she said.