Draught of love
The old man sat down next to Han Xin at the table, and Han Xin poured him a cup of tea. The steam curled up between them as the old man continued, "The sleeping thorn plant isn't easy to find. It grows in the grasslands of the east. To gather enough of it, someone would have had to travel for months and then return the powder to Yige. It's too much work for a poison when there are plenty of others that are more easily accessible and cheaper. They especially brought it for a wolf in my opinion."
Han Xin nodded thoughtfully. "If the sleeping thorn flower is addictive to wolves, would that make them aggressive?"
The old man took a sip of his tea, savouring the warmth. "Yes, the wolf would become aggressive if it didn't get its fix. It would follow that scent until it found what it needed."