Construction of the Mine
Within a month of the meeting, Thomas Percy rented a house adjoining parliament where it was determined that they should dig a mine, beneath the parliament house, that would be filled with gunpowder. Due to his unknown status, Guy was placed as caretaker of the house assuming the alias John Johnson.
At the end of the summer, the plotters returned to begin work on digging the mine. However, on their return, they were foiled. Due to its location close to parliament, the house was requisitioned by the Crown for use by the Scottish Lords, who had travelled to London to negotiate the union between the Crowns of England and Scotland. This would later prove the first step in the establishment of Great Britain.
After negotiations ended in early December, work began on the mine, ceasing on Christmas Eve. While the conspirators disbursed for Christmas Guy stayed alone to watch the house. On 28 December he was present at a wedding in Whitehall between the Earl of Montgomery and the niece of Robert Cecil.