Having just bombed Pydyr, the Dark Jedi Kueller wanted to use detonators concealed within droids to blow up the Senate Hall during the opening session following an election, so as to begin his hostilities against the New Republic and to send it into a political crisis. The droids were manufactured and fitted with the explosives on Telti, under the guidance of Brakiss, and smuggled into Coruscant by a smuggler called Jarril.
The senate session began and Chief of State Leia Organa Solo welcomed in the new senators, such as Meido, who had been former Imperials and had been allowed to stand for election following the introduction of new legislation. The droids with detonators within them were placed mainly around senators loyal to the New Republic, rather than around the former Imperials, and detonated. The explosion rocked the chamber and shrapnel rained down everywhere, while pieces of the crystal ceiling began falling to the ground and tiles put in by Emperor Palpatine came loose and fell across the hall like hail. The explosion also caused shock waves that caused surrounding buildings, like the Crystal Jewel, to shake.
The explosion devastated the interior of the Senate Hall, but caused no major structural damage to the exterior. It killed 25 senators, including M'yet Luure; a number of senate guards; and injured another 100 senators. Leia Organa Solo also received minor injuries and was temporarily made deaf.
A contingent of guards and medical personnel was soon sent out to help the injured. Han Solo also rushed to the hall to check that Leia was unharmed. Leia was convinced that the former Imperials had something to do with the attack, although Han believed that it had something to do with Jaril, who at the time of the explosion had been trying to warn him about something. Han and Chewbacca decided to travel to the Smuggler's Run to investigate this theory further. Luke Skywalker also came to the chamber following the attack and was able to feel through the Force that it had not been one large explosion, but several smaller ones and that Brakiss was in some way connected to it.
The majority of the former Imperials were unharmed and gained proportionally greater power, causing the development of a powerful new faction in the senate under the de facto leadership of Meido. They obtained circumstantial evidence to implicate Han Solo with causing the explosion and attempted to use this to force a vote of no confidence and get Chief of State Solo out of office.