“What keeps you going now?” I ask. “Anything?”

“Not at first,” he says, frowning. Then he shrugs it off. “But now there might be a little something. . . .” His voice trails away, but before I can press, he points ahead. “I think that’s the park.”

It’s a vast expanse of green lawn over artificial hills, with walking paths throughout. The word “Sandusky” is formed on a hillside using some kind of pink flowering plant, though it’s already overgrown and knocked around so that the n looks a little like a p and the k is more like an l.

“Let’s circle around the park,” I suggest. “Look for a tower.”

We do, and each time we hit an intersection, the break in buildings and trees leaves an unobstructed view to Sandusky Bay, stretching flat and gray. Sometimes we even catch glimpses of the swirling Wicked Twister and the towering Millennium Force—two of the tallest roller coasters of Cedar Point. Which makes me think of Ryan, who was terrified of roller coasters, though he made me swear to tell no one. Maybe I’ll honor that secret to my grave.

Tanq bangs on the window, and Trey nearly loses control of the wheel in his attempt to find cover. But she keeps tapping, and I realize she hasn’t spotted an aircraft; she’s trying to tell us something.

I twist in the seat as she mouths, Pull over!

“Tanq says to pull over,” I tell Trey, and he does, parking near a giant clock built out of the ground with hedge bushes and flowers.

Trey flings the door open and rounds on Tanq. “You nearly gave me a heart attack!”

“Follow me,” Tanq says, ignoring him. “I saw a sign.” Eyes to the sky, she splashes through puddles in the street, heading away from the park.

She leads us to an old brick house that looks like it was built at least a hundred years ago. It’s surrounded by modern buildings, which makes it stand out. A sign in the front lawn establishes it as the LUCAS BEECHER HOUSE.

“Not that sign,” Tanq says, and she points, shifting our gazes to the right. “That one.”

It’s a historical marker that says UNDERGROUND RAILROAD in big bronze letters across the top. Below is more text, but the writing is obscured by a big tag—a circle with a diagonal line through it—this one spray-painted in bright red.

“Did Null get as far as Sandusky?” Trey says. “I thought he operated mostly in Columbus and Cincy.”

“If so, that’s racist as hell,” I say. “Nullifying the Underground Railroad?”

“That’s not what this is,” Tanq says. “It’s what we’re looking for. ‘Follow the rail,’ remember?”

“How do you know?” Trey asks.

“I know. Trust me.”

Trey says, “Sandusky was a major stop on the Railroad to Canada. There might still be hidey-holes all over this city.”