Swamped

"Why does he look so purple?" you ask.

"That's grape juice," the doctor says. He sounds concerned, but still calm. "I think someone tried to poison him with it, but since he was unconscious, it seems they just poured it over him in hopes that enough of the toxin would make it into his system."

"Oh," you say. Somewhat awkwardly, you follow up with "And is that the problem?"

"No. The unconsciousness is the problem we're trying to solve. He may be slipping into a coma. The assailant left the juice glass, so I had Stephanie analyze it."

You think you might know the cause of that.

"I noticed some little bits of leaf on his table earlier. You don't suppose that could have something to do with it?"

"We've been studying some swampleaf that induces sleep, but I've never heard of it having an impact this severe," the doctor replies. "And I've read a lot of letters from the swamp..."

He suddenly trails off, as if he's said too much. You decide to act as though you don't think much of it.

"Who's even in the swamp sending letters?" you ask calmly.

He seems to hesitate before giving an answer.