He always wore a somber three-piece suit that looked oppressively hot. The only hint of decoration he wore was a silver tie clip with a little bird clinging to a slim branch. It was so heavily stylized that she must have seen it half a dozen times before she spotted the bird in the intricate silverwork.

“Tell me about the tie clip,” she said. “It’s surprisingly whimsical for such a serious, sober man.”

He touched the tie clip, flushing a little. “It’s a memento of my greatest professional failure.”

“Oh?”

“The Kestrel Gang. A dangerously clever group of counterfeiters. I’ve been hunting them for a decade. Once I spent almost a year in St. Louis on their trail, but it came to nothing.”

“Why are they called the Kestrel Gang?”

“Kestrels are the smallest breed of falcon. They are smart, tricky, and migrate all over the nation, which is how this gang of counterfeiters operates. Somehow they figured out that the Secret Service code name for them was kestrel, and they sent me this tie clip after I gave up in St. Louis.”

She smothered an appalled laugh. “And you choose to wear it?”

Amusement danced in his eyes. “It’s a daily reminder for me. I’ll catch them someday.”

Oddly, learning of his professional failing and his sense of humor about the tie clip made him even more attractive. She liked his old-school formality, especially now that they were outdoors and he had dropped the stalking cat demeanor.

“Why do you scrutinize the tourists so intently? There are plenty of ushers keeping watch.”

“I’m educating myself.” At her quirked brow, he continued. “When looking for counterfeit bills, you don’t study fake currency, you study the real thing. Thousands and thousands of authentic bills of different denominations, age, and wear. Only by being intimately familiar with what the real thing looks like can I spot the fakes.”

“And the tourists?”

“Same principle. None of them look alike, but I’m studying how they behave. Some are excited to be here, others look hot and tired. Some are distracted by fussy children. Some gawk at the ostentation while others are moved by patriotic emotion. All these things are normal. I need to observe thousands of examples to get it engraved in my mind so that when someone who isn’t really a tourist shows up, I’ll spot him.”

He went on to explain that the notes he compiled would be provided to the rest of the security guards. Most of the guards had worked here for decades but probably had no formal training other than some fighting and shooting experience. Nathaniel was going about things much more methodically.

“Who is the guest you’ve asked to visit the White House next Monday?” he asked.