And now he had written to her. Having read the note, she put it into the bosom of her dress, and, whilst her fingers were busy, she turned over every possible explanation in her mind. She knew that he had abandoned his evil habits of late, and she could be just enough not to refuse Totty some credit for the change. Gilbert himself had said that the girl's influence seemed on the whole good. But some mystery was now going to reveal itself. It concerned Thyrza; she was sure it did. The fact that the note was delivered in this way, and the request for secrecy which it contained, made this certain. At dinner-time, and again in the evening, Thyrza was still in the same state of depression and feverishness. Lydia said nothing of the business which would take her out at eight o'clock. When the time came, and she had to make an excuse, Thyrza said that she too would go out; she wanted to see Totty. 'You'll tell Gilbert?' Lydia replied, afraid to make any opposition herself. 'No. He'd say it wasn't good for me to go out, and I want to go. You won't say anything, Lyddy?' 'I ought to, dear. You're not well enough to go, that's quite certain.' 'I won't be long. I must go just for half an hour.' 'Why do you want to see her?' Lydia asked, masking her curiosity with a half-absent tone. 'Oh, nothing to explain. I feel I want to talk, that's all.' From time to time--in her more difficult moments--Lydia had felt a little hurt that the course of circumstances made no difference in Thyrza's friendship for Totty. When her truer mind was restored, she knew that the reproach was a foolish one. More likely it was she herself who was to blame for having always nourished a prejudice against Totty. At present, Thyrza's anxiety to go out was another detail connecting itself with Ackroyd's summons. Something unexplained was in progress between those three, Totty and Ackroyd and Thyrza. Her resentment against the first of them revived. She would soon know what it all meant. Thyrza and she left the house together and went in opposite directions. Lydia crossed Kennington Road, and found Luke waiting for her. She approached him with veiled eyes. 'I'm so glad you've come,' he began, with signs of disturbance, 'It's kind of you to come. I have a great deal to say, and I can't speak here. Will you come round into Walcot Square?--it'll be quieter.' She said nothing, but walked beside him. It was a new and strange sensation to be thus accompanying Ackroyd. She was conscious that her pulses quickened. They went on in silence till they reached the spot which Luke had mentioned, an irregular little square, without traffic, dark. 'I don't know how to begin to tell you, Miss Trent,' Ackroyd said, when he stopped and turned towards her. 'It's your sister I have to speak about.' She had foreseen truly. Her heart sank. 'What can you have to say about my sister, Mr. Ackroyd?' she asked in a hard voice.