“You can’t save every animal you think might not be optimally happy, you know.” Nathan squeezed my shoulder. “I wish you could, but you’d run out of room at the shelter before you ran out of animals that needed help. I run into something similar with patients. I want to help them all. I can’t.”

“Time and insurance are cruel masters,” I said automatically. I still couldn’t take my eyes off the dog. The jogger had stopped and was scolding his pet now, although they were too far away for me to hear what he was saying. The dog pulled harder on her leash, and barked, once. That sound was loud enough to carry, and several other heads turned toward it. Dogs barking in the city wasn’t anything unusual. Dogs barking in that much evident distress was.

Maybe we weren’t the first ones to witness what happened next; maybe other people saw it happen before we did. But those people didn’t tell anyone what they’d seen—maybe didn’t understand what they’d seen—and we did. That made all the difference in the world.

First the jogger dropped the leash. It fell to the grass, and the dog ran several yards before turning back to face her master, barking again. She was a good dog. I could tell she was a good dog, even without knowing her name or why she was so unhappy. A bad dog would have run as soon as she had the chance. This dog looked back to her master, waiting for whatever was wrong to go away and leave things the way they were supposed to be. I abandoned all thoughts of a dognapping when I saw the look the dog was giving to that man, to her man, as she waited for things to fix themselves.

The man didn’t move. For several seconds, he didn’t move at all. Then all the tension went out of his shoulders and neck, leaving his head to loll limply forward. Several more seconds passed. Nathan’s hand tightened on my shoulder.

“I don’t like this, Sal,” he said. “Whatever this is, I don’t like it. We should get out of here.”

“But the dog—”

“Will be fine.”

“What if he’s having a seizure or something? Shouldn’t you see if you can help?”

Nathan shook his head. “This doesn’t look like the start of a seizure. I don’t know what it is, but it could be viral, and it’s not something I’m equipped to deal with.”

The man raised his head.

The dog immediately started barking again, her ears going flat against her head and her posture going rigid, something I recognized from the shelter as a sign that she was about to attack. Without thinking about it, I put two fingers in my mouth and whistled. Her head whipped around, ears going back up, and she broke into a sudden run, heading straight for us.

“Oh, crap, she’s going to attack!” said Nathan, and pulled me backward, seeming set on physically removing me from the scene if that was what it took to keep me from getting savaged.

I pulled my shoulder out of his grasp. “No, she’s not,” I said, and dropped into a crouch just as the dog reached us. She practically flung herself into my arms, whining frantically. She stank of urine, a hot, acrid smell. At some point during the confrontation with her master, she must have pissed herself.

“What did he do to you?” I muttered, and raised my head, intending to give the dog’s owner a piece of my mind. Then I froze, arms tightening around the still-whimpering dog. She plastered herself hard against me, like she thought she could somehow protect us both by cowering just a little more thoroughly.

The man—her master—was walking toward us with his arms held out for balance, a blank look on his utterly slack face. He looked like the people Joyce and I had seen at the mall; he looked like he was sleepwalking. All around us, people were shouting and pointing at him. Many of them were filming his shambling approach with their phones. The footage would be all over the Internet before the news crews even showed up.

This time, when Nathan pulled on my shoulder, I didn’t pull away. Instead, I scrambled to my feet, grabbing the dog’s leash at the same time. She whined, but she came willingly as the three of us turned and ran, as fast as we could, away from the Embarcadero.

We arrived back at the hospital winded and sweaty, having run the first two blocks and walked the rest. Only the dog seemed unaffected, probably because she belonged to a jogger—keeping up with me and Nathan had to seem like a walk in the park to her.

Just thinking the word “park” made that uneasy feeling in my gut reappear. I staggered to a stop just inside the lobby, catching myself against the wall with my free hand as I gasped for air. The dog sat down by my feet, assuming the patient waiting posture that has been the characteristic of the Labrador retriever since the breed was born.

Nathan stared at the closed door, and then turned to stare at me. “Did you see that?” he asked needlessly. I looked at him without saying a word. He grimaced. “I’m sorry, I know you saw that, of course you saw that, but that was—he was perfectly normal, and then he was just…”

“Gone,” I whispered. I pushed away from the wall and knelt next to the dog. She had a full set of tags. I dug through them until I found the one with her name. “He was gone, and Beverly here was all alone. Weren’t you, Beverly?”

The dog—Beverly—looked up at me with warm, trusting brown eyes. I was a human. I had her leash, and I knew her name. Clearly, I was going to make everything okay. It must be nice to be a dog.

“I have to notify the ER. They need to send someone to pick him up…” Nathan raked a hand through his hair before whipping around to look at me. “Can you wait in my office for a few minutes? I promise, I’ll be there as fast as I can.”