When Clo telephoned, Ellen Blackburne did not even know that the Sands were out of New York. The message, however, instantly awoke her sleeping interest. She guessed that Clo had tracked the thief, and that what she called the "weird address" given was the "lair." Miss Blackburne was no coward, and the astonishing request that came over the telephone wires did not frighten her. She prepared to follow instructions at once, taking only one precaution. Before starting, she left word that if she did not 'phone or return within an hour, inquiries were to be made at the house and in the street whose number she wrote down. The pearl-stringer did, therefore, precisely what she had been asked to do. She abandoned the work laid out for the morning, and dashed off in a taxi on a moment's notice. Clo's little face at the window of a tenth-rate boarding-house told her nothing new. Clo was always pale. When the girl dropped to her knees it looked to Ellen as if that attitude were more convenient for throwing down the bag. No sound of a pistol shot reached Ellen's ears over the noises of the street. She heard only the "teuf-teuf" of her own taxi, and the snort of a big gray car which had at that instant come to a stop close by. Miss Blackburne was used to odd adventures, and prided herself on "keeping cool," but she could not help giving an undignified jump as a man sprang out of the gray limousine and laid a hand on her arm. "What is in that bag and where are you taking it? I've a right to know," he said sharply. "I'm a friend of Miss Riley." Ellen grabbed at the door of her taxi. The man was about thirty or thirty-two, she thought, certainly a gentleman and rather handsome. "I'm acting for Miss Riley," she returned as sharply. "My name's Blackburne. Clo's in a hurry for me to do an errand. If you're really her friend, you'd better let me get away while you look after her." The two eyed each other for an instant. "You are Miss Ellen Blackburne, the pearl-stringer?" the man inquired. "The same," she answered. "Then go on her errand!" he exclaimed. And while Ellen stared, he ran up the steps of the house where a companion had already rung the bell. Neither of the men looked again at her. Ellen waited for no more. To save delay and further suspense for Mrs. Sands she drove straight to the Park Avenue house, in order to string the pearls there: for she had hastily collected her materials before starting. It was a blow to hear from the hall porter that the Sands had already left New York; she decided on going up to get further information. She even thought of sending a long-distance message to Beverley from her own flat; but the grim personality of Anna Schultz banished this idea at a glance. Ellen realized that if she asked to enter the apartment she would be regarded as a suspicious character. Important business with Mrs. Sands would take her to Newport immediately, she told Miss Schultz. If there were any letter or parcel to be sent she would carry it.