Frost stared at the three wooden planks fixed to the side of a sheer cliff face, making a walkway barely eighteen inches wide. There was no railing, just swags of chain nailed to the rock like Christmas tinsel. On the open side of the planks, the cliff descended straight down into a thousand feet of air. Gnarled, wind-swept trees sprouted from its rocky crevices. Misty mountains filled the distance.

As he examined the weathered beams mounted on the rock, a five-year-old with a vanilla ice cream cone ran through the open canyon to her mother. The tourists crowded around the painting in Ghirardelli Square laughed nervously. It was just a three-dimensional sidewalk illusion, but it was so real that Lucy, with her vertigo, would have fainted.

Frost sat down next to the artist on the stone steps of the plaza’s mermaid fountain. Water gurgled and splashed over brass turtles and bare breasts. The morning sun cast shadows across their faces. The iconic chocolate factory sign loomed above them, and he could smell sweetness in the air.

“Impressive, Herb,” Frost said. “Please tell me that’s not a real place.”

“It is, actually. That’s the famous plank walk on Hua Shan mountain in China.”

“Have you done it?”

“I have.”

Frost wasn’t surprised. Herb was the kind of man who’d lived ten lifetimes in almost seventy years. “And why would anyone do something like that?” he asked.

“A Buddhist would probably say to gain enlightenment,” Herb replied, “but honestly, I was stoned out of my mind.”

Frost laughed. The omnipresent aroma of pot from Herb’s paint-stained flannel shirt was enough to intoxicate anyone who spent too much time with him. He had leathery white skin, dark eyes, and black glasses with tiny magnifiers for close-up work. He was skinny and tall, and he limped because of the time he spent painting on his knees. Shack sat in the artist’s lap, and the black-and-white cat batted at the multicolored beads strung into Herb’s long gray hair.

They’d been friends for fifteen years. Even in a melting pot city like San Francisco, Herb was one of a kind. He knew everybody. Hippies. Fishermen. Gays. Radicals. Yuppies. Techies. He’d spent four terms on the city council in the ’80s, but for as long as Frost could remember, he’d simply painted elaborate sidewalk illusions around the city. He’d been featured on The Tonight Show and Good Morning America and had appeared in a dozen San Francisco–based movies.

“I was at your brother’s food truck a couple days ago,” Herb said, tickling Shack’s chin. “Looks like he’s doing well.”

“He is. Duane loves it. It’s a big change from the brick-and-mortar kitchens.”

“And your parents? How are they?”

“Enjoying Arizona. They bought a golf cart, which I find truly horrifying.”