What did the letter to the king say about the gunpowder plot?

The letter to the king regarding the Gunpowder Plot, written by one of the conspirators, warned about the planned attack on Parliament and the assassination of King James I. It detailed the conspirators' intentions to use barrels of gunpowder to blow up the House of Lords during the State Opening of Parliament. The letter aimed to alert the king to the imminent danger and prevent the conspiracy from being executed. Ultimately, it contributed to the foiling of the plot, leading to the arrest of the conspirators.