There was almost a command in Grey's tone, but Ethel did not offer to move.
"But it is impossible," she persisted. "How could I leave Arnold Rent? What would his mother say when she heard what I had done?"
"Nevertheless, you must do exactly what I tell you," Grey went on. "There is a mystery which must be solved, even thought it breaks Mrs. Rent's heart, and you suffer into the bargain. And if you will allow Mr. Charlock to take you quietly home, I will pledge my word that Arnold Rent shall come to no harm. Within an hour I will see that he is back."
Ethel would have ventured some protest, but the stern, hard expression on the speaker's face checked her. She turned almost imploringly to Charlock, as if seeking his protection.
"I don't understand," she murmured. "The whole thing is inexplicable. Still, if you must have your own way, I will bow to the inevitable. Mr. Charlock, would it be too much trouble to ask you to come as far as——"
"Not in the least," Charlock said eagerly; "it would be a pleasure. And I hope you won't think Mr. Grey censorious. He is acting for the best."
"I pledge my word to that," Grey said, with a stern ring in his voice. "Believe me, Miss Hargrave, I am not here on pleasure bent. But the truth must be told, even only for the sake of innocent people. I will do my best not to abuse the trust you have put in me. I promise you that before long Arnold Rent shall be safe back in bed again. Meanwhile, there is one thing I must ask you to do. As you go along the quay you might stop and tell the boatman who is waiting to row me back to the yacht that Dr. Tanza is wanted at once. Don't say more than that, for Tanza will know what I mean. I don't think I need say more."
Silently Charlock offered his arm to Ethel Hargrave, and they vanished into the darkness. No word passed between them till after they had interviewed the sleepy boatman and sent him off on his errand. Then Ethel turned to her companion and faced him resolutely.
"I think you are a good man," she said, in a voice that shook a little. "At any rate, I know you to be generous and truthful. Now, Mr. Charlock, kindly tell me what all this means. What is the object of so much mystery? Why could not Arnold Rent have accompanied us home instead of staying behind in that gloomy old house? It is hardly fair to two defenceless women to make them puppets in a game like this."
"I swear I cannot tell you," Charlock said passionately. "I really don't know. But I am sure Grey knows what he is doing and will never rest till he gets to the bottom of the mystery."