The note contained only a simple, four-line poem, written in florid script. She held it close to the lamp to make it out.

Where true Love burns Desire is Love’s pure flame;

It is the reflex of our earthly frame,

That takes its meaning from the nobler part,

And but translates the language of the heart.

—S. T. Coleridge

A pretty enough verse, but utterly unhelpful. No salutation, no signature. Her heart deflated with disappointment. She turned the paper to the reverse side, scanning it closely. Nothing there, either.

Then she returned to the verse. She decided to read it aloud, slowly. Perhaps there was some sort of message within.

“Where true Love burns Desire is Love’s pure flame,” she read aloud. “It is the reflex of our earthly—”

She stopped and blinked. Now she was seeing things. She could have sworn that words were dancing between the lines of the verse.

She held the paper closer to the lamp, directly over the flame. As she watched, a word materialized on a blank space of the paper, darkening to sepia one letter at a time.

l—a—t—e

Late.

Invisible ink!

There was a message hidden between the lines of the poem.

Exhilarated, Charlotte pushed through the jumble of hairbrushes and ribbons on her dressing table until she located the curling tongs. She used them to hold the paper over the flame, letting the heat touch every corner, as if she were toasting a slice of bread. The tediousness of the exercise tried her patience to its limits, but she didn’t dare risk letting the paper catch fire.

When at last she’d heated every inch of the paper, she smoothed the note on the flat surface of the table. The invisible message read:

The ladies will meet Tuesday next

Please bring in the conserves and crumpets

Both are obligatory at midday nuncheon

Such damp nights of late.

Crumpets?

Crumpets and humidity.

This was the mystery message. Of all the inconsequential, nonsensical lines to inscribe in invisible ink and perfume with rich scent.

Whoever these mystery lovers might be, Charlotte was annoyed with them both. Midday nuncheon, indeed.

She rubbed her eyes and read it again. Then she ran the paper over the flame once more. Nothing new appeared.

Perhaps it was some sort of code? She tried reading it backward, reading every second word, every third or fourth letter . . . none of these methods yielded any comprehensible message.

She was on the verge of crumpling the thing and tossing it into the fire in disgust, when she noted a tiny dash of sepia where she wouldn’t expect it to be. She’d dismissed it before as a stray droplet of invisible ink, but now she noticed that it was centered perfectly beneath one word of the poem: “frame.”

With her fingertip, she scanned the paper for any other small, overlooked markings. She found another dash; this one directly beneath the word “heart.”

Frame and heart.

Heart and frame.

On a hunch, she found a scrap of paper, trimmed it to match the size of the note, and then folded it down the middle and made a swooping cut with a penknife, removing a heart-shaped piece from the center. Then she laid her makeshift valentine over the note, sliding it around until it seemed centered.

The frame blocked out nearly all of the hidden message. The still visible parts read:

will meet

in the conserv

atory at mid

night

“Oh, Lord.” She rose from her chair, jumping back in disbelief. “I . . . I’ve done it. That’s it. ‘Will meet in the conservatory at midnight.’ ” She laughed aloud. “I, Charlotte Highwood, have decoded a secret message, and I’ve done it all by myself. Take that, Agent Brandon.”

Now she felt like dancing. But there wasn’t time. Someone was expecting a clandestine lover to arrive in the conservatory at midnight, and Charlotte had been working at this for ages. It had to be getting close to the hour.

She checked the mantel clock.

Oh, no. Five minutes past!

Charlotte rushed downstairs.

She crept to the door of the conservatory and opened it silently before sliding inside. The space was dense with the misty fragrance of a thousand blossoms. The glass windows were fogged.

Weak, flickering light spilled from a distant corner of the indoor garden.

A trail of rose petals on the tiled floor led into the conservatory, then disappeared around a bend some ten feet ahead. Perfume, poetry, rose petals . . . ? Whoever this lover was, he or she was truly a romantic.

She paused, suddenly hesitant.

Did it even matter who waited at the end of this trail? It was too late to redeem her reputation, and it wouldn’t change her dilemma with Piers. But it would mean so much if she could regain Delia’s friendship. Finding the lovers would mean a great deal to her pride, as well. By society’s standards, she wasn’t accomplished. This was her chance to prove them all wrong.

In any event, she’d come this far. The mystery would haunt her forever if she didn’t take these last few steps.

She held her breath as she followed the trail of red, velvety petals. When she turned the corner, her heart pounded in her chest.

The fragrant mist of the hothouse parted to reveal a dark, tall figure.

There, standing in a leafy, candlelit alcove was . . .

“Piers?”

He made an elegant bow. “Good evening, Charlotte.”

“What are you doing here? Did you find a note, too?” She looked around. “Were they here already? Did you see them?”

“Did I see whom?”

“The mystery lovers! Or tuppers, or whatever they might be. I found a perfumed note in the ballroom, in code. It took me ages to decipher it, until it was almost too late, and then I hurried down to—”

As she spoke, she took in more details of the scene. The brass candlestick fitted with a beeswax candle. The bottle of champagne chilling in a silver ice bucket. The picnic hamper.

The sly smile on Piers’s face.

“It was you.” She slapped a hand to her forehead. “You left the note. For me.”

“The rose petals were Ridley’s idea.” He reached for the bottle of champagne and popped the cork. “Did you enjoy your investigative work?”

“You tricked me.”

“No, I didn’t. You’re here, aren’t you? That means you weren’t tricked at all.” He handed her a glass of champagne and nodded at the paper in her hand. “That message used the same methods, more or less, as General Benedict Arnold employed to send intelligence during the rebellion of the American colonists. You deciphered it. Well done.” He raised his glass to her, then drank from it.