Theo gave a rather strained smile at Snape's comment, nodding. "I thought so, yes," he said. "I have not worked this many years making up cover stories not to sense one when I come across one - a poor one at that."
He pondered the situation as Snape went on. He had no qualms about killing the man who had held the wand who had killed his daughter in order to gain the Dark Lord's trust. Granted he had not actually killed a man before, but he'd experimented enough with the Dark Arts. His father had made sure he knew how to kill.
"Artefacts won't be a problem," he said, as he pondered how his position might play a part. "Most artefacts are protected in such a way that any attempt to remove them from the building will lead to severe injury on the person attempting it. The ones that are not protected with these kinds of spells are few and less important, and more importantly there is no reason for me to tell the Dark Lord of their existence."
"A larger concern is him asking me to find information for him, something he has already done once," he said, reaching out his hand and summoning a parchment and quill. Drawing the symbol on the parchment he pushed it towards Snape. "I've been looking into the meaning of this symbol for the last few weeks. So far I've managed to tie it to a children's fairytale, the Tale of the Three Brothers, and a legend of a wand that makes the caster invincible. I have found little to no reference to the cloak and stone mentioned in the fairytale, and what I have found is contradictory and suggests that it's mere myth."
"Of course I have not shared any of this information with the Dark Lord, and I need to discuss with the Minister how much to give him and how much to hold back."
"Granted if I am going deeply under cover then that changes what I must and mustn't say."