The newspaper slipped from Patricia's lap to the ground and she looked surprised. "I don't understand!" "If you will do an errand for me I will give you five pounds." "Oh, I can do an errand for you without taking money." "I don't ask-you to: this is rather a dangerous errand. But I think you are brave, and I know that you are hard up----" Patricia interrupted. "I have enough money to go on with," she said, flushing. "At ten shillings a week!" retorted Mrs. Pentreddle, unpleasantly. "Well, please yourself!"--she turned over on the sofa--"I have given you the chance." Miss Carrol thought hard during the silence which ensued. Certainly, in her pauper condition, five pounds would be a god-send, and, as she had determined to lay aside all pride when she gave up the position to which her birth entitled her, she considered that she might as well take what she could get at this difficult stage of her fortunes. For five pounds she would do much, but---- "Is the errand an honest one?" she asked suddenly with a catch in her voice. The thought had just struck her. "Perfectly honest," said Mrs. Pentreddle coldly. "What is there about me that you should think me capable of asking you to do something wrong?" "Nothing at all," confessed Miss Carrol frankly; "but if you wish me to go on a mysterious errand, it is only natural that I should desire to hear everything about it." Mrs. Pentreddle carefully lowered her injured foot to the ground, and sitting up very straight, folded two thin hands on her lap. "You shall hear," said she quietly, "only I must request you to keep your own counsel." Patricia nodded. "That goes without the saying," was her answer, and she again wondered if the five pounds could be earned honestly. "I came up to London to go on this errand myself," explained the old lady slowly, "but this sprain has prevented my keeping an appointment which must be kept to-night. As the matter is important, I am willing to pay you the money on your return with It." "It? What is 'It'?" "A small deal box you can easily carry in your hand. A man will give it to you if you will stand at nine o'clock by the right-hand corner of that bridge which crosses the Serpentine. On this side, remember, before you cross the bridge. Nine o'clock, and you must hold this"--she fished amongst the cushions of the sofa and produced a small bull's-eye lantern, the glass of which was pasted over with red paper. "This is the signal." "The signal?" echoed Miss Carrol, rather nervously, for all this mystery did indeed hint at something criminal. "Oh, you needn't turn so white," said Mrs. Pentreddle scornfully. "What I ask you to do is perfectly straightforward. There is nothing wrong about it." Patricia still hesitated, vaguely afraid to be implicated in such unusual doings. "If you will explain further, Mrs. Pentreddle----"