jack said no more for the present. he closed the front door quietly, not forgetting, however, to glance at the great clock, and stopping to calculate that a good half-hour must elapse before anstruther returned. it would have been a great misfortune indeed if the latter had come home at that moment. in a mechanical kind of way serena turned into the dining-room, where she proceeded to pull down the blinds and switch on the lights. at a sign from jack, lady barmouth remained where she was for the moment, and masefield, together with claire, entered the dining-room.

"i am bound to ask you a few questions," he said, turning to serena. "for instance, i have yet to learn why the walking image of that poster should have frightened you so terribly."

"it was adolpho returned from the grave," serena murmured. apparently she was talking to herself. "beyond all question poor adolpho----"

she paused in some confusion, and looked guiltily from claire to jack. the latter was not slow to take up the point.

"so you have actually seen the man before?" he demanded. "well, we will not discuss that at present. a little later on perhaps i shall ask you to speak more freely. meanwhile, i may as well tell you that i came here to-night with a lady desirous of seeing you."

serena was alert and eager in a moment. jack could see that the fighting look had returned to her face; her eyes dilated strangely. she seemed to guess by some subtle instinct exactly what was going to happen.

"my sister," she whispered. her voice was very strained and low. "something tells me that my sister is here. i pray you go away and get rid of her at once. tell her any lie, invent any falsehood. if you have the slightest feeling for the most miserable woman in the world you will do this thing for me."

"but it is too late," jack protested. "lady barmouth is with me; she is waiting in the hall at the present moment, and she has already seen your face."

"but i do not understand," serena cried, stretching out her hands hopelessly. "i have but one sister whom i believe to be living, and her name is grace. lady barmouth cannot possibly be anything to me."

"lady barmouth is your sister all the same," jack explained. "she married lord barmouth after you left home; she has told me your sad story, and you must believe that she has been looking for you everywhere. surely you would not punish yourself for that which was after all merely an act of girlish folly?"

serena covered her face with her hands and burst into tears. her head fell forward on the table. presently an arm stole about her neck. when she looked up again it was to meet the tender and softened gaze of lady barmouth.

"and so we meet again like this after all these years," lady barmouth said gently. "oh, my dear serena, how could you go off like that; how could you leave us all without a word or a sign? our father was a harsh man; his pride was his besetting sin, but he would have forgiven you and taken you to his heart again if only you had returned to the old home. didn't you suppose that i cared? and after all said and done, what is your crime? you trusted a man who was not worthy of your affection, and he deserted you because you lacked the money for which he married you. if that is a crime, then there are many thousands of poor women in the world in the same sad plight."

meanwhile jack and claire had crept quietly from the room. it would have been indelicate to remain there in the circumstances. jack, looking at claire, noted that the tears were also in her eyes.

"what a strangely pathetic thing," claire murmured. "how did it come about, jack?"

jack explained the story of the photograph, but claire was hardly listening. it seemed such a strange, sad story to her, this pathetic meeting between the two sisters.

"but you don't suppose that mr. anstruther knows?" claire asked. "you do not imagine for a moment that he is aware of the fact that serena is lady barmouth's sister?"

"i hope to goodness no," jack exclaimed. "but i don't see how the thing could be possible. to begin with, the sisters are not in the least alike, and in addition to this serena had not the least idea that lady barmouth had married. what i am most afraid of now is that anstruther should come back and discover those two women together."

"claire nodded gravely, with one eye on the clock. it was only a matter of minutes now when anstruther would return. he was dining at his club to-night, claire explained, with mr. carrington, at eight o'clock, and as it was now a quarter past seven, there was not much time for him to dress and get back to st. james's street again.

"in that case i must intrude myself upon those two ladies," jack said firmly. "i will put lady barmouth in a cab and send her home. it will be quite easy for the sisters to arrange a meeting at lady barmouth's house. keep anstruther out of the dining-room if he comes in."

jack strode resolutely across the hall, and placed the matter tersely and vigorously before the sisters. "it would never do," he explained, "for anstruther to find you here at this moment."

serena's eyes were swollen with weeping. there were the deep marks of tears upon her cheeks. lady barmouth's worldly training had stood her in better stead, but she also carried traces of emotion which could not be wiped out in a moment.

"i am going to put you in a cab at once," jack said. "anstruther may be here any instant, and you can imagine how necessary it is to keep him in the dark. besides, you can easily arrange a meeting in a safer atmosphere than this."

with a brief remark to the effect that she would communicate with serena again, lady barmouth left the room, and permitted jack to escort her to a cab. the latter breathed more freely as the clatter of the horses' hoofs died away. he ran back quickly to the house again to give a few last words of instruction to claire.

"you look all right now," he said, "but serena's case is entirely different. take my advice, and send her up to her room. if you are not going to dine in the proper sense of the word, there is no reason why serena should appear again till anstruther has gone to his club. and i will go, too; i don't want our worthy host to know that i have been here this evening."

jack went off thoughtfully in the direction of the square. it was a particularly good-class neighborhood, and generally very quiet at this time of the evening. the half-hour past seven had just struck from a neighboring clock. in most of the dining-rooms on the north side of the square brilliant lights demonstrated the fact that folk were at dinner. with the exception of a solitary policeman nobody was in sight. as is usual with the majority of london squares, the place was none too well lighted, and there were just sufficient lamps to throw the shadows of the garden in deeper relief. it had often occurred to jack how easy crime and violence would be in circumstances like these.

jack's imagination was working freely now; indeed, it would have been odd if his brain had not been screwed to a high pitch by the events of the day. coming towards him now, swinging along at a good pace, was a tall, slim figure, which seemed familiar to masefield. as the figure paused under a lamp to look at his watch, jack could see the figure was that of anstruther. he congratulated himself upon the fact that he had got away from panton square before anstruther returned. he crossed the road in a casual sort of way, and passed along under the shadow of the houses so that anstruther had no idea how he was being watched.

the latter paused again, just by the entrance to the square gardens, the gates of which had not yet been locked, though it was considerably past the hour when the gardens were closed to the public. anstruther stood there as if debating something in his mind, then suddenly another figure came like a lightning flash from inside the garden gates, and fell upon anstruther with terrible swiftness.

so sudden and unexpected was it that jack could hardly believe the evidence of his own eyes. anstruther gave one gurgling cry, his hands went up as if imploring assistance, then he settled down to a fray which could only end in one fashion. it was impossible where jack stood for him to make out anything more than the mere outline of the man who had so unexpectedly fallen upon anstruther. but there was no mistaking the grimness of his intention: there was sinister design in every movement of the body this was no common square thief, intent upon a paltry meed of plunder, but a man who had deliberately picked out his prey with the intention of mauling it to the death.

all this passed as it were in the twinkling of an eye. jack knew now that he would have to pull himself together and advance to the rescue. as he flew across the road he heard in a mechanical sort of fashion the heavy footstep of a policeman clanging on the quiet pavement some little way off. here, at any rate, was aid fairly close at hand. but jack was not the kind of man to wait in an emergency like this. before he could cross the road he saw that anstruther was prostrate on the pavement, with his assailant kneeling cat-like upon his chest. the man was evidently fumbling for something, probably a weapon of the noiseless kind, for jack could see his right hand working in a hip pocket. with a headlong leap jack fell upon the would-be assassin, and clutched him by the throat. at the same time a police whistle shrilled.

but the man kneeling on anstruther's chest was not taken aback for an instant. with a quick upward motion of his body he pitched jack clean over his head, and, rolling off anstruther's chest, darted like a snake into the gardens. by this time three policemen were upon the scene. "no, i don't think he is hurt much," jack explained, as anstruther scrambled to his feet, and gazed wildly around him. "no damage done, eh?"

anstruther explained that he was none the worse for his adventure. he seemed to be under the impression that he had been the victim of some loafer's cupidity. he could give no description of his assailant; indeed, he said that he had no idea now but to get away and keep an important appointment. he tossed his card over to the police, and went coolly down the road.

"we can get that fellow all the same," jack said. "he is in the gardens somewhere. suppose you three men stand round the square while i go inside and drive him out. one of you lend me a lantern."

the quest was by no means a long one. at the fourth cast of the lantern jack descried his man crouching down under a belt of laurels. he reached forward and dragged the fellow up by the neck.

"i am a bigger man than you are," jack said. "do you come quietly, or are you going to take it fighting?"

by way of reply the man raised his hat; his face was exposed.

"i am not going to take it at all," he said. "you will be good enough to put the police off my scent and have a cab handy so that i can get away without being seen. we have met before, sir."

it was a fitting crown to a day of surprises. for the man who stood before jack was the same nostalgo he had conveyed in the guise of a dead body to shannon street police station.