Fortunately, he only made a quick loop around the service hallway and reception room. “So this is it?”

“I think so,” Iris said, thumbing through her notes. “Everything but that locked room on the third floor. I think the mechanical chase stretches from the third floor to the roof. There are access doors and large grates in the bathrooms. I could almost see in one of them.”

“Cold-air returns. Anything else?”

“I don’t think so . . .” Iris frowned. Just the ghost of a lost secretary locked up in a suitcase and a madman breathing in the air shaft, she thought. The unbearable heat of the fifteenth floor was making her dizzy.

As if he read her mind, Brad headed toward the service elevator.

Once her ears had popped halfway down the tower, she remembered. “Oh! And the tunnels.”

“Tunnels?” Brad lifted an eyebrow.

“Yeah, Ramone says there are tunnels in the basement that lead to other buildings, like old steam tunnels.”

“Awesome! Let’s go check it out!”

“Do you think they need to be included in the schematics?”

“Nope, but don’t you want to see if we can find Jimmy Hoffa down there? Come on, it’ll be fun!”

Brad wanted to do something on company time for fun. She could not have been more surprised if he had suggested they go smoke a joint in the bathroom or torn off his shirt to reveal a giant tattoo.

As they stepped off the elevator into the lower level, the slam of a door thundered down the hall. Iris turned toward the noise.

“Ramone?” she called out.

She headed past his bedroom and around the corner. The vaults were empty. The slam must have come from the door to the spider-infested stairwell that led up to the loading dock.

“Looks like he took off,” Brad said behind her.

“I guess we’re on our own.” She managed a smile despite the nagging feeling in her gut.

“Did he say they were on this level?”

“Well, he said ‘basement.’ This is the basement, right?” She said it and realized the vault room looked nothing like a basement. Basements had pipes and boilers and dripping water. She glanced back at the vaults lined in bronze and marble, and it occurred to her that bank customers must have come through there from time to time to access their safe deposit boxes. Rich people with priceless valuables definitely didn’t use the spooky service stairs. The service elevator wasn’t fancy enough either. How did they get down there?

She pulled out her plans and compared what they had drawn for the basement with the main banking level. She and Brad had surveyed the lower level together, so she hadn’t doubted its accuracy until that moment.

Sure enough, they were missing a column bay to the north underneath the main lobby. Her fingers traced the monumental staircase that flanked the east wall. The stairs stepped down from the lobby. Holding the plan like a treasure map, Iris headed east and north, until the giant vault door stopped her in her tracks. It stretched from the ceiling to the floor and was swung open against the wall.

“Brad.” There was no response. “Brad?”

“Yeah?” He stepped around the corner from the service elevator.

“We’re missing something on our plan. The building keeps going twenty more feet that way.” She pointed at the giant metal door. Brad grabbed the plans and looked them over.

“You’re right. Good catch!”

“This closes, right?” she asked, pointing to the giant steel circle blocking her way. It was the door to the larger vault where the bank had once stored its cash reserves.

“Well, it is a vault.”

Iris tried not to roll her eyes in annoyance. “Let’s try to close it. It’s not like there’s anything in the vault anyway.”

She gave it a pull, but it wouldn’t budge. Brad walked over and gave it his all. No luck.

“There has to be a trick to it.” Brad searched the perimeter of the round door.

Iris scanned the rest of the room and located a small red button on the far wall. She walked over to it and pushed it as Brad was pulling on the door with all of his might. The door sprung free and sent Brad sprawling on the floor with an oomph. Iris slapped a hand over her mouth to keep from laughing.

“I see you smiling.”

Brad stood up and brushed himself off. He grabbed the door and walked it closed. As the circular door swung shut to seal the cash vault, it revealed a round entryway, which led to another room.

“Clever,” Brad said, walking through the portal. “They use the vault door to block access to the room when the vault is open.”

Iris nodded and stepped through the round doorway. The room beyond the vaults was twenty feet wide and ran the length of the building. It was dark except for the faint light coming from the far end. Iris clicked on her flashlight. There was a small security station and a long reception desk. At the west end of the room were three small booths. Red velvet curtains were drawn to conceal a chair and a small table inside each little chamber.

“What the hell are these?” Iris asked, pulling a curtain aside.

“This must be where people went to open their deposit boxes, eh?” Brad pulled out his tape measure and set about correcting their floor plan.

While Brad busied himself, Iris walked across the soft red carpet to the far edges of the room, trying to find access to the tunnels. The walls of the lower lobby were wood and inlaid bronze, just like the main lobby above it. The faint light grew brighter as she made her way past the elevator bank and around the corner. Trapped sunlight streamed down the marble stairs from the lobby above.

Stairs were always stacked one on top of the other in a building. Maybe there were more of them. She searched the dark-wood panels cladding the triangular section of wall under the stairs until she found it. There was a door-sized panel cut into the wood beneath the upper landing. It was perfectly flush with the surrounding wall and the tight seam along its edges was barely visible. She ran her hands along the perimeter and found nothing—no handle, no hinges. When she pushed on it, a latch clicked. The panel swung open to a small service closet.

“Brad! I found something!” she called over her shoulder as she stepped into the hidden passageway and saw a metal service door marked “Utilities.” She tried the handle. It was locked.

“Hey there, Sherlock! You found it!” Brad said, trotting up to her side.

“It’s locked.”

“You got the keys.”

“Oh, right.”

Iris fumbled in her field bag while Brad looked over her shoulder into her tangled mess of pens and fast-food wrappers. She could feel him smirking as she struggled to find them. The keys Brad had given her were buried in a side pocket next to her cigarettes. It took five tries, but she finally managed to wrench the door open.

“After you,” he said, swinging his arm to the door with a bow. Brad was a dork.

Iris blindly felt inside the wall until she found a small light switch. A bare bulb at the bottom of the stairs clicked on. The stairs to the basement were steep, with open metal grates for treads. Iris stepped down nervously as they wobbled beneath her. A nest of spiderwebs hit her face before she reached the last step, and she struggled not to screech like a girl. At the bottom of the stairs, there was a narrow passageway. Pipes and conduit raced overhead down the narrow hallway and out of sight.

“These must be the tunnels,” Brad said from behind her.

“Yeah, but how are we supposed to know where they’re going?” Iris asked, peering into the dark.

“They left breadcrumbs.” He pointed to a small plaque on the wall next to the stair that read “First Bank of Cleveland.” He clicked on his flashlight and began heading down the tunnel. “Let’s see where this takes us.”

Iris nodded reluctantly and followed him down the narrow hall, ducking her head so as not to hit the tangle of pipes and wires overhead. Through puddles, falling insulation, and dangling wires, they walked for what seemed like five city blocks until they came to a larger room. The walls were old brick, and the brick ceiling vaulted over them like a Roman aqueduct.