Luke shrugged. “I can’t do that without exposing my partner in crime.”

“Twinkle Toes?” Caroline asked.

The term made no sense to Nathaniel but seemed to annoy Luke, who sent his sister a tight smile.

“Darling, you know I adore you, but I’d rather that highly confidential information not be shared with your rule-following Romeo.”

“We can trust him,” she said. “He works for the Secret Service, which answers to the Treasury. It’s completely independent of the military.”

The sarcasm vanished from Luke’s face, replaced by a look of speculation. “How much do you trust him?” he asked Caroline.

“With my life,” she said promptly.

Her unflinching endorsement cut through Nathaniel’s annoyance. He grasped the arms of the chair to stop from bolting across the room to continue their kiss where he’d left off.

Luke closed his eyes, then leaned over to brace his forearms on his thighs. All teasing was gone as he rubbed his jaw and stared at the floor.

“Sorry, Caroline, but I can’t trust him. The last fifteen months have been too rough for me to risk it all on Romeo.”

Something was going on. Why had Caroline drawn the distinction between the Secret Service and the military? Who had Luke been working for? Nothing was clear to him, and his investigative instincts kicked into gear. He wanted to pull on this thread and see where it led, but Luke wasn’t going to allow it.

Caroline’s eyes were apologetic as they met his. “Thank you for coming over tonight,” she said. “I’m sorry I can’t ask you to stay. . . .”

She looked exquisitely uncomfortable as the sentence dangled, and he stood. He wouldn’t make this any more difficult than necessary, but he wouldn’t leave without saying good-bye either. He closed the distance between them and cupped a hand beneath her chin, tilting it up as he leaned down and kissed her, long and deep.

“Meet me outside in an hour,” he whispered into her ear. He had to see her alone. The past weeks had been brutally hard, but the first ray of light had pierced the darkness.

He gave her a quick, final hug, then slipped away.

Nathaniel waited on a bench across the street from the Delacroix townhouse, still astounded over the events of the past hour. He was happy for Caroline. Having her brother back home was her dearest wish in the world . . . but it was worrisome too.

Relief for Caroline mingled with his strangling sense of guilt. Over the past weeks he’d completely abdicated his professional duties. Worse, his despondency had been a needless distraction for people shouldering immense duties during the crisis of the assassination and the presidential transition.