Charles was overwhelmed by a sense of catastrophe.  Here was a possibility which had been overlooked.  How was he to instil belief that he spoke the truth?  A moment passed.  Thalassa cast another black look at him, and turned as if to walk away.  “I’ll keep my word,” he muttered to himself.

The young man’s quick ear caught the whispered sentence, and saw the way.  “I’ll prove it to you,” he said.  “You promised Sisily that you’d tell nobody she was at Flint House to see her father on the night he was killed.  How could I know that unless I’d seen her?”

“What else?” said Thalassa, facing him with a strange and doubtful glance.

“You let her in,” Charles rapidly continued, “and you waited downstairs for her.  Afterwards you took her back across the moors to catch the wagonette.  It was on the way, near the cross-roads, that Sisily made you promise not to tell anybody that she’d been there that night.”

“Suppose it’s true—­what then?” Thalassa’s voice was edged with the craftiest caution.  “She’s sent you to me to ask for the truth, say you.  ’Twould have been safer not.  What else is there to say, when she’s told you everything?” He cast a look of savage jealousy at the young man.

“Much.”  Charles spoke rapidly, but his glance was despairing.  “What happened while you were away from the house?  What sent your wife mad?  What did you find when you returned?  You know these things, Thalassa.”

“Happen I did, what good’d come of telling them?”

“To save Sisily.”

“They’d not help to save her.”

“Do you think she shot her father?”

Thalassa gave him another dark look, but remained silent.

“You know she didn’t, you hound!” cried Charles, anger flaring up in him again.  “It was you—­it must have been you.  Listen to me!  I know almost enough to hang you.  I was in the house while you were away, and found your master lying dead in his study, and the key of the door in the passage outside.  Who could have dropped it there except you?”

“’Tweren’t me.  ’Twas done afore I got back to the house,” answered Thalassa.

“What time was it when you left the house with Sisily?”

“Agone half-past eight:  perhaps ten minutes after.  She came running downstairs, her eyes staring and blazing.  ’Thalassa, dear Thalassa, for pity’s sake let me out,’ she said half-sobbing.  ’Oh, what did I come for?  He’s wicked—­wicked.’  Twasn’t for me to say anything between father and daughter, so I just opened the door without a word, and went out with her.”

“What time did Sisily catch the wagonette?”