Confrontation in the Republic Executive Building

"I trusted Palpatine. I thought he was my friend; I couldn't have been more wrong. I know know that he was, is, and always will be, truly evil. I am truly fortunate that I resisted him that night; if I had not, then I fear things would've been much different."

- Anakin Skywalker

The Duel in the Chancellor's Suite was a lightsaber duel between the Dark Lord of the Sith, Darth Sidious, and Jedi Masters Mace Windu, Kit Fisto, Saesee Tiin, and Agen Kolar in the Chancellor's Suite of the Republic Executive Building.

The duel originated from Anakin Skywalker's discovery that Supreme Chancellor Palpatine was none other than Darth Sidious, the Sith Master who was behind the war, controlling both the Republic, and the Confederacy of Independent Systems. When Sidious revealed this to Skywalker, the latter informed Mace Windu, and Windu, along with fellow masters Kit Fisto, Saesee Tiin, and Agen Kolar, went to arrest Sidious, in order to stop the Sith threat and remove him from power.

The Jedi made their way into Palpatine's suite at the Republic Executive Building, and prepared to arrest the Sith Lord. However, after a very brief conversation, Palpatine attacked the Jedi, quickly killing all but Windu. The two engaged each other in a brilliant lightsaber duel, but Palpatine eventually proved victorious, slaying the Jedi Master.

Sidious appeared to be victorious, but as he prepared to order the 501st legion of the Grand Army of the Republic to attack the Jedi Temple, and issue Order 66 to the clone troopers, turning them against their Jedi commanders, galaxy-wide, Skywalker entered the Chancellor's suite, along with Masters Obi-Wan Kenobi and Yoda, who had just returned from Utapau and Kashyyyk, respectively. Thus, another lightsaber duel ensued, in which Sidious urged Skywalker to join him, but the young Jedi tore off the influence of the dark lord, destroying the darkness within himself in the process.

Overpowered, and realizing that the one he'd sought to turn to the dark side would never embrace it, Sidious was forced to abandon his plans, and flee Coruscant. As a result of the confrontation, Palpatine's insidious schemes were revealed to the public, which changed public opinion on the former leader of the Republic. Shortly after, the Jedi Council took temporary control of the Galactic Senate, and this lasted until elections were held for a new Supreme Chancellor

Prelude
"Be careful of the Jedi, Anakin. Only through me can you achieve a power greater than any Jedi; learn to know the dark side of the force, and you will be able to save your wife from certain death." "What did you say?" "Use my knowledge, I beg you." "You're the Sith Lord!"

- Palpatine reveals his true identity as Darth Sidious to Anakin Skywalker

In his dreams, Jedi Knight Anakin Skywalker had been plagued with prophetic visions of his secret wife, Padmé Amidala, dying in pain during the birth of their child, which greatly agonized the Jedi; he became convinced that, like the vision he had of his mother dying, the one about his wife would come true, and both she and their child would die.

Meanwhile, Supreme Chancellor Palpatine, Anakin's mentor and friend, invited him to a show at the Galaxies Opera House so they could speak in private. While they sat in Palpatine's private box, he told Skywalker a Sith legend, "The Tragedy of Darth Plagueis the Wise," informing him that Plagueis had discovered the ability to save others from death by manipulating the midi-chlorians within the cells of bodies. Plagueis had taken a Sith apprentice and taught him everything that he, as a Sith Lord, knew. However, Plagueis' apprentice, wanting to usurp his power and position, murdered the Dark Lord in his sleep. Skywalker became very intrigued in this power, believing that he would be able to learn, and use it successfully to save Amidala, and their child, from death.

Later, in the Supreme Chancellor's office, Palpatine finally revealed himself to be Darth Sidious, Plagueis's former apprentice and the current Dark Lord of the Sith, causing divided loyalties in Skywalker, as he was divided, inside, between his desire to learn the Sith power and his duty as a Jedi to turn the dark lord in. He thought of killing Sidious on sight, as it was his duty as a Jedi to eliminate the Sith, but he could not bring himself to kill his former mentor and friend.

Departing from Palpatine's suite, Skywalker quickly went to the Jedi Temple, informing Jedi Master Mace Windu of Palpatine's true identity, though he was greatly conflicted about doing so. Sensing his internal conflict, Windu sent Skywalker to the High Council Chamber, advising him to spend time meditating upon his conflicted emotions. Windu then took a squad of Masters: the Nautolan Kit Fisto, the Zabrak Agen Kolar, and the Iktotchi Saesee Tiin—to arrest Palpatine in his office.

Sidious expected a showdown, and he prepared well for it; sensing the approach of the Jedi Masters onboard a gunship. Sidious recovered his lightsaber from its resting place within a neuranium sculpture, hiding the hilt in the sleeve of his robe. When the Masters dispatched the Chancellor's private guards beyond the office's outer doors, the Sith Lord triggered a concealed recording device—that was audio only. The Jedi strode into Sidious' private office, where Master Windu declared the Chancellor was under arrest. However, by altering the audio recording, the Sith Lord ensured that, when the recording was released publicly, he would be portrayed as the victim, with the Jedi appearing unnecessarily aggressive towards the seemingly innocent old man.

The duel
"Master Windu; I take it Master Kenobi has destroyed General Grievous, then. I must say you're here sooner than expected." "In the name of the senate of the Galactic Republic, you are under arrest, Chancellor." "Are you threatening me, Master Jedi?" "The senate shall decide your fate." "I am the senate!'" "Not yet, Lord Sidious." "It's treason, then."

- Mace Windu and Palpatine, immediately prior to their duel