The girl had on a small squirrel toque and a long squirrel coat. She was wrapped in a squirrel rug to match. She had reddish-brown hair. All the girls who can take the last men in the world away from all the other women have more or less of that red glint in their hair. Yet she seemed far from anxious to take the man who came striding along the deck and stopped in front of her as the ship got under way.

What she did was to look up and cry out a horrified "Oh!" Her cheeks, which had been pale, flamed red. She half threw off her fur rug, and would have struggled out of her chair if the man had not appealed to her mercy.

"Don't run away from me, Grace," he said, "after all these months."

The name "Grace" suited the girl, or rather expressed her. The man stared with hungry eyes. I was sorry for him. Somehow, I seemed to know how he felt. He had an American voice and looked like an American – that good, strong type of American who can hold his own anywhere: not tall, not short, not slim, not stout, not very dark, not very fair; square-jawed, square-shouldered; aggressive-featured, kind-eyed; one rebellious lock of brown hair falling over a white forehead.

"But – I have been running away from you all these months. I've been doing nothing else. I could do nothing else," she reproached him. They had both forgotten me. Besides, I was not obtrusively near.

"Don't I know you've been running away – to my sorrow?" he flung back at her. "I heard of you in the West Indies. I went there to hunt you down. You'd gone. I dashed home. You hadn't come back. I was told – I won't say by whom – that you were in England. I ran over and got on your track yesterday; flashed off to Bath in a fast auto; reached there just as you'd left for Liverpool to sail on this ship. So now I'm here."

She looked up at him, tears on her lashes. "Oh, Rod!" was all she said. It did not need that name to tell me who he was, but eyes and voice told me something more. She was not flirting with him. She was not pretending to wish that he had not come. With all her heart and soul she did wish it, yet —she loved him. I wondered if he knew that, or if not how much he would give to learn it.

"You can't get away from me this time," he said, not truculently, but pleadingly, as if he were afraid she might somehow slip out of his hands. "We'll have five days and a half – I hope six – together. If I can't persuade you in five days and a half – "

"You couldn't in five hundred years and a half! Rod, what do you think of me? Do you suppose I want you to die?"

"Do you suppose I'm afraid?"

"No. But I am – for you. Nothing on this earth can induce me to change my mind. You only make us both miserable by keeping on. Oh, Rod, here comes Aunt Marian! This is her chair."

Roger Odell glanced in the direction the girl's eyes gave him. I did likewise. A woman was coming, a tall woman in brown. A generation ago she would have been middle-aged; in our generation such women are young. She looked about thirty-eight, and so I put her down as ten years older. She was dusky olive, with a narrow face, banded black hair, and a swaying throat: rather a beautiful Leonardo da Vinci sort of woman.

Evidently she was as much astonished to see Odell as the girl had been, but she had a different way of showing it. She did not seem to mind his presence when she got over her surprise. She shook hands and let him put her into her chair, tucking the brown fur rug around her body and under her slim feet. I thought she seemed more Italian than American. She was very agreeable to Odell, in a cool, detached way, but when she inquired if he ought not to be going below to lunch, even a man of his determination was obliged to take the hint. "We are having something brought to us on deck," she explained. "Come back if you like when you have finished."

My lameness gave me an excuse for troubling the deck steward, who fetched me a plate of cold chicken at about the time when more elaborately furnished trays were placed before the two ladies. They had more to eat than I, but they finished sooner; at least, it was so with the younger. There was no sea on, yet she left her luncheon almost untouched, and after five minutes' playing with it went indoors. No sooner had she got safely away than Odell came back to accept the invitation given by "Aunt Marian," only to find it no longer worth his acceptance. (Recalling her words, I realised that she had never expected "Grace" to stay.) Odell asked for a chair, nevertheless, and had it put next to hers, evidently meaning to annex the place permanently. These were the right tactics, of course. Even I should have adopted them; but they were opposed to a more subtle and deadly strategy. "Grace" proceeded to prove that being on board the same ship with her did not mean being in her society. She did not appear on deck again. Odell was forced to realise that he had made the girl a prisoner in her cabin.

That afternoon the list of passengers was given out, and I searched eagerly for her name. I had not far down the alphabet to go. There she was among the "C's" – "Miss Grace Callender." The name was an electric shock; and seeing it I could guess but too easily why the girl might love a man and run away from him.

Nobody who read the newspapers three years ago could have helped knowing who Grace Callender was; and if they forgot, she would certainly have been recalled to their minds a year and a half later. I, at least, had not forgotten. I owed to the "Callender-Graham Tragedy" one detail which had helped to make the success of my novel, and had suggested its name, The Key. Miss Callender was (and is) an American heiress, but England has its own reasons for being interested in American heiresses. Therefore, at the time of the two great sensational events in Grace Callender's life, London papers gave long paragraphs to the story.

Her parents – cousins – were both killed in a motor accident in France while she was a schoolgirl at home in charge of her aunt, a half-sister of the father, Graham Callender. Both parents were rich, having, for their lifetime, the use of an immense fortune, or rather the income derived from it. The principal could not be touched by them, but passed to their only child. This arrangement had come about through a family quarrel in the previous generation; but, as Graham Callender and his wife were of opinion that injustice had been done, they wished their daughter to atone for it by her marriage. Half the money ought rightly to have gone to Philip Callender-Graham, a cousin who had been disinherited in their favour. He had died poor, leaving a couple of sons a few years older than Grace. The two had been educated at Graham Callender's expense, and had spent their holidays at his houses in town and country. Grace had grown up to look upon both almost as brothers, though they were only her second cousins. She was fond of the pair – a little fonder of Perry, the elder, than of his younger brother Ned. As for the brothers themselves, it appeared later that both were in love with Grace; but Ned kept his secret and let Perry win the prize. The engagement of Grace Callender and Perry Callender-Graham was announced on the girl's nineteenth birthday. One night a few months later, and just one week before the day fixed for the wedding, Perry Callender-Graham was found dead in a quiet side street near Riverside Drive.

There were no marks of violence on his body, and apparently he had not been robbed. In his pockets were several letters which could have no bearing on the cause of his death, an empty envelope, a sum of money, a jewel-case containing a diamond pendant, probably intended as a gift for his fiancée, and two keys which seemed to be new. Both were latchkeys: one rather large and long, looking as if it might belong to the front door of a house; the other was small, not unlike the key to the door of the dead man's flat. Neither fitted any door of the private hotel in which he lived, however, and consequently suggested mystery. But as three specialists certified death by natural causes, the police came to regard the keys as of no importance. The doctors testified to a condition known as "status lymphaticus," which cannot be diagnosed during life, but which may cause a slight shock to be fatal. It was thought that Callender-Graham – whose body lay close to a street crossing – might have started back to save himself from being run over by a swift automobile suddenly turning the corner, and in the shock of falling have died of heart failure.

Grace Callender was grieved and distressed, but not prostrated with sorrow, as she would have been over the loss of an adored lover. Everyone who knew her knew that she had been going to marry her cousin not because she was in love, but in order to give him the fortune wrongfully diverted from his father. In these peculiar circumstances, many people prophesied the thing which happened a year later: her engagement to Ned Callender-Graham, through whom the restitution could equally well be made. He seemed to be a popular fellow, even better liked in general than his dreamy, poetical brother; and as his friends guessed that he had unselfishly stood in the background for Perry's sake, all were pleased with his good fortune. The engagement went on for six months; and then a week before the wedding was to take place, Ned Callender-Graham was found dead in the same street and almost on the same spot where his brother had fallen a year and a half before.

This extraordinary coincidence was rendered even more remarkable by the fact that nearly every detail of the first tragedy was repeated in the second. Not only had the brothers met their death in the same street, and almost on the eve of marriage with the same girl, but, according to doctors' evidence, they had died in the same way and at practically the same hour. Ned, like Perry, was afflicted with status lymphaticus. There was no trace of violence on his body. He had not been robbed, for his pockets were full of money. He carried his brother's watch which Perry's will had left to him – the watch which Perry had worn on the night of his death – and two or three letters, together with an empty envelope. Stranger than all, perhaps, he had in his possession two new latchkeys – duplicates of the keys found in his dead brother's pocket.

This time, owing to the almost miraculous resemblance between the cases, foul play was suspected. But it seemed that the brothers had no enemies and, so far as could be learned, no serious rivals with Miss Callender. The girl and her aunt clung to the belief that Perry and Ned had died natural deaths, and that the ghastly coincidence was no more than a coincidence. Miss Marian Callender's theory was that Ned had fallen a victim to his love for his brother, a too sensitive conviction of guilt in taking Perry's place, and an unhappy superstition which he had confided to her – though, naturally, not to her niece. He believed himself to be haunted by his brother's spirit, which influenced him to do things he did not wish. He said one day that he doubted if Perry would ever let him marry Grace, but would contrive to break off the engagement in some way, even if all went well until the last moment. Miss Marian Callender suggested that the apparently mysterious keys were the same keys which Perry had possessed, they having been given, with other souvenirs of the dead man, to his brother; that it was characteristic of Ned to keep them by him, as well as the watch, in a kind of remorseful loyalty to the brother he had superseded; and that the same half-affectionate, half-fearful superstition had led him that night into the street where Perry had fallen. Once there – at an hour the same as that of Perry's death a week before his appointed marriage – in all probability Ned had imagined himself confronted by his brother's accusing ghost. The two were known to be temperamentally as well as physically alike, though Ned was undoubtedly stronger physically. It was not strange if Perry had a peculiar weakness of the heart that Ned should have the same; and the shock of a fancied meeting with Perry's spirit at such a time and such a place might easily have been too great for a man already at high nervous tension. Others than Miss Marian Callender talked freely with reporters and detectives, repeating her story that Ned Callender-Graham had felt oppressed with a sense of guilt, that he had worried himself into an emotional state which he had tried to hide, and that he had attended spiritualistic séances. All this, together with the fact that there was no evidence of murder, caused the second verdict to be the same as the first. But Grace Callender found herself so stared at and pointed at, and gossiped about wherever she went, that her life became a burden. She knew that terrible nicknames were fastened upon her, that she was called "Belladonna" and "The Poison Flower," as if her promise to marry had brought death upon her lovers. She heard women whispering behind her back, "If I were a man I simply shouldn't dare be engaged to her in spite of her millions"; and what she did not hear she imagined. She in her turn grew superstitious, or so it was said. She began to feel that there must be something fatal about her; that a curse which the father of Perry and Ned was said to have pronounced on her parents in his first fury at losing a fortune had been visited on her. Though she had twice come near her wedding she had never yet deeply loved a man; nevertheless, because of the "curse" and in fear of it, she resolved to give up all hope of happiness in love, never to marry, nor even engage herself again.

All this I remembered distinctly, not alone because my memory is a blotting-pad for such cases, but because the story had captured my imagination, and because I had used the detail of the keys for my own book, only substituting one for two.

"By Jove!" I said. "The key! Now, can that be the clue to Roger Odell's veto?"

I set myself deliberately to think the matter over from this new point of view. Evidently he was desperately in love with Grace Callender. Could the mere fact that I had named a book of mine The Key, and turned my plot upon a mysterious key found in a dead man's pocket, have inspired Odell with revengeful rage? Except for the title, and the key in the pocket, there was nothing in my book or in Carr Price's play which bore even the vaguest likeness to the Callender-Graham tragedy. I didn't see how the most loyal lover could feel that I had "butted in" upon what to him was sacred; still, the new idea had some substance in it. Not only had I hit on a possible clue to the man's enmity, but into my mind from another direction suddenly flashed so astounding a ray of light that I was almost blinded. I could hardly wait to try weapons with Odell.

How to get at him and hold him, so to speak, at my mercy was the next difficulty. I had to think that out too, and I did it by process of deduction. For reasons of my own, I had not yet secured a seat in the dining-saloon, but now I limped down below with my inspiration. Others had made their arrangements and gone, but I managed to catch the head steward.

"I suppose you're assigning seats for people who want to sit alone at these small tables?" I began.

"We have assigned only one such, sir," he cautiously admitted. "All we're able to give."

"Why all?" I wanted to know. "There are plenty of tables and only a few passengers."

"Yes, sir, that's true. But also, there's only a few stewards. We haven't enough to spare for scattering around."

"Is Mr. Roger Odell the one fortunate person to whom you've been able to give a table to himself?" I threw out this question like a lasso.

"Why, yes, sir, as a matter of fact he is," the caught steward confessed. "We've several tables with parties of two or three, but for one alone – "

"I may wish to be alone just as much as Mr. Odell does," I argued. "But the next best thing to being alone is to sit with another man who wants to be alone. Then there's no fear of too much conversation. Put me at Mr. Odell's table." As I spoke I slipped a five-pound note into a surprised but unresisting hand. (I had to bribe high to outbribe a millionaire.) Even as his fingers closed mechanically on the paper the steward's tongue began to stammer, "I – I'm afraid he may object, sir."

"He may at first; but not after three minutes. All I ask is to be put at the table when Mr. Odell is seated, and without his knowing beforehand that he's obliged to have a companion. If he still objects after three minutes of my company I've had my money's worth. I'll leave him in possession of the table; you can put me where you like."

It was a bargain. The steward pointed out the table selected by Odell.