"It came from House Tyrell after you were made a new [lord/lady]. It was hidden among taxation ledgers. I suspect they didn't know they were sending it."
"Well it has come to our hands. Therefore, we shall further investigate its secrets."
Results
'Lucas nods. "Your cousin is at your court currently. I shall ask him to go to Highgarden, speak to Lord Mace about the book, and find the Knot to open it."