This photograph, located northwest of the Kaaba, shows the approximate location of Darun Nadwah (House of Assembly). The house functioned as a chamber of parliament for Quraysh, and it was from here that they planned to kill the Prophet (ﷺ). Please note that this area is in the new Haram expansion project.

Qusay bin Kilaab built Darun Nadwah about 150 years before the birth of the Prophet (ﷺ). The house was used for public meetings; Discussions were held to address important issues, such as war and peace, caravans assembled before going out, and marriages and other ceremonies. It was from here that the battalions received their flags before going to battle.
Quraysh leaders gathered in Darun Nadwah to draw up a plan against Islam and Muslims.
When Islam in Mecca gained strength, and Quraysh feared that their power would be undermined, they gathered a special council to discuss how to get rid of the Prophet (ﷺ).
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Iblis/Iblees (Satan) was also present at this meeting under the guise of Sheikh Jaleel from Najd. Some of the leaders of Quraysh believed that they should expel the Prophet (ﷺ) from their territory, while others believed that they should imprison him until his death. Finally, Abu Jahl put forward his idea that each of them must choose a strong youth from his tribe, arm them with swords and strike the Prophet (ﷺ) at a time. By killing the Prophet (ﷺ) in this way, all clans will have a share of his blood and the Prophet’s defenders (ﷺ), Banu Abdu Munaf will not be able to simultaneously capture all Quraysh. Iblees (Sheik Jaleel) commended the plan, and the Quraysh set their trap.
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However, Angel Jibraeel (peace be upon him) came to the Prophet (ﷺ) and told him about the conspiracy to kill him. That night, the Prophet (saw) asked Ali (may Allah be pleased with him) to sleep in his bed, assuring him that he would not be harmed, and he himself managed to slip away unnoticed. Only at dawn did the Quraysh understand that it was Ali (may Allah be pleased with him) that was sleeping on the bed and that they were deceived. Regarding this incident, Allah mentions in Sura al-Anfal: “Remember how unbelievers plotted against you to imprison you, kill you, or drive you out of Mecca. They plan and plot, but Allah plans too, and the best of planners is Allah. ” [Quran 8:30]
Sources: The History of Makkah Mukarramah – Dr Muhammad Ilyas Abdul Ghani, When the Moon Split – Shaikh Safiur-Rahman Mubarakpuri