On the whole, Prelice arrived at certain conclusions, by no means inimical to Mrs. Rover, by the time he alighted at Hythe Station. He believed that Constance was innocent for four reasons. Firstly, if guilty, she would not have confessed to wearing the dress, since such a confession would necessarily lead to her detection. Secondly, by killing Agstone she would not only have placed Shepworth in a dangerous position, but by getting rid of an inconvenient witness would have enabled Mona to escape possible condemnation. Thirdly, she would not have followed an unknown man--as Prelice was by reason of his mask and domino--down the stairs with the intention of seeing what took place. Fourthly, and lastly, she would not have sought safety in an incriminating flight--as the similarly dressed woman on the stairs apparently had--when she would have been much safer in her own ballroom and amongst her own guests. Only by such a course could she have provided an _alibi_. No! Mrs. Rover, in spite of her startling admission, was innocent, and the sole conclusion that Prelice could arrive at, was the existence of a double--outwardly at all events. He remembered the extraordinary ubiquity of the green domino in the red-streaked white dress, and decided, very naturally, that there was another woman in the field. But what woman possessed a motive sufficiently strong to urge her to murder Agstone? As Prelice felt quite worn out with arguing in Mrs. Rover's defence, he decided to leave the answering of this new question to the portentous moment, when further evidence might reveal the identity of the unknown lady. Meanwhile, on arriving at Hythe, he rested himself at a quiet hotel, and soothed his troubled brain with an hour's necessary sleep. Later on, after an invigorating bath and an excellent dinner, he started to walk towards Lanwin Grange.