deduces elaine tracking

Then I slid the bag over my shoulder, went into the living room, and wrought the spell that would lead me to one of the very few only people who might help.
Half an hour later, I paid the cabbie and walked into one of the hotels surrounding O'Hare International Airport. The subtle tug of the spell led me to the hotel's restaurant, open for breakfast and half full of mostly business types. I found Elaine at a corner table, a couple of buffet plates scattered with the remains of her breakfast. Her rich brown hair had been pulled back into a tight braid and coiled at the base of her neck. Her face looked pale, tired, with deep circles under her eyes. She was sipping coffee and reading a paperback novel. She wore a different pair of jeans, these a lot looser, and a billowy white shirt open over a dark tank top. She stiffened a beat after my eyes landed on her, and looked up warily.
I walked to her table, pulled out the chair next to her, and sat down. "Morning."
She watched me, her expression opaque. "Harry. How did you find me?"
"I got to thinking that same thing last night," I said. "How did you find me, that is. And I realized that you hadn't found me - you'd found my car. You were inside it and nearly unconscious when I got back to it. So I looked around the car." I pulled the cap to a tire's air valve out of my pocket and showed it to her. "And I found that one of these was missing. I figured you were probably the one who took it, and used it to home in on the Blue Beetle. So I took one of its mates from the other tires and used it to home in on the missing one."
"You named your car after a superhero on the Electric Company?" Elaine reached into a brown leather purse on the chair beside her and drew out an identical valve cap. "Clever."


Summer Knight Chapter 24, Page 284-285