The Senate hostage crisis represents an event that unfolded within the Senate Office Building on the planet of Coruscant amidst the backdrop of the Clone Wars. Bounty hunters, under the employ of the Hutt Clan and commanded by Cad Bane, seized control, holding Supreme Chancellor Sheev Palpatine of the Galactic Republic and a number of senators captive. Their objective was the liberation of Ziro the Hutt from the confines of the Republic Judiciary Central Detention Center.

During the Clone Wars, Ziro, who was the uncle of Jabba the Hutt, faced arrest at the hands of the Republic's Coruscant Guard alongside Padmé Amidala, a Senator representing Naboo. Ziro confessed to collaborating with Count Dooku, a Separatist leader, in a plot to kidnap Jabba's son, Rotta, with the aim of seizing control over all Hutt Clans. Following this admission, Ziro was subsequently incarcerated within the Republic's detention center.
Subsequently, Ziro engaged Aurra Sing, a bounty hunter, to assassinate Senator Amidala. However, after the attempt failed, Jabba and the Grand Hutt Council grew concerned that Ziro might disclose their records of the Council's illicit activities to the Senate. Consequently, Jabba compensated Cad Bane, another bounty hunter, to acquire the Galactic Senate Building's blueprints from C-3PO, Amidala's protocol droid. Despite 3PO's lack of the blueprints, he revealed that R2-D2, Anakin Skywalker's astromech droid, possessed them. Bane successfully obtained the blueprints after capturing R2, before wiping the droids' memories of the ordeal to avoid suspicion. Returning to Jabba's Palace on Tatooine, Bane received payment for the blueprints. With the Council's approval, Jabba then contracted Bane to execute the mission of rescuing Ziro, which Bane accepted for a suitable price.

Bane assembled a team of bounty hunters, consisting of Aurra Sing, Shahan Alama, Robonino, HELIOS-3D, HELIOS-3E, another IG-86 sentinel droid, and a pair of commando droids. Together, they proceeded to the Senate Building. Bane encountered resistance from Senate Guard commandos and Captain Jayfon. Sing eliminated the commandos, after which Bane and the remaining bounty hunters dispatched the rest. Subsequently, the commando droids disguised themselves as Senate Commandos, enabling Bane and his team to enter the building.

During this period, Jedi Knight Anakin Skywalker was in a clandestine meeting with his wife, Senator Amidala. Their meeting was interrupted by Senator Bail Organa, who requested Amidala's presence at a meeting with Senator Philo regarding the Enhanced Privacy Invasion Bill. Amidala accompanied Organa, leaving Skywalker behind, but inadvertently took Skywalker's lightsaber with her.
Bane and his bounty hunters navigated through the building, eliminating the remaining Senate Guards along the way. They then infiltrated the Control Room, subduing the droids and guards stationed there. Bane tasked Robonino with cutting off the power supply. Subsequently, Bane and the rest of the team approached the senators to talk.

Bane and his bounty hunters encircled the Senators, taking them hostage. Senator Philo resisted Bane's demands and attempted to leave, prompting Bane to shoot him. Bane then contacted Supreme Chancellor Sheev Palpatine, demanding Ziro's release and handover. Initially, Palpatine refused, but Robonino's subsequent power cut, which locked down the building and severed external communications, changed the situation. Bane proceeded to search the Senators for communicators. Upon encountering Amidala, Bane noticed Skywalker, prompting him to dispatch Alama and the IG-86 sentinel droid to pursue him. Skywalker attempted to contact someone but was unsuccessful.
Skywalker faced Alama and the droid but realized he lacked his lightsaber. Consequently, he evaded them and sought a room with communication equipment. There, he modified his comlink and contacted Palpatine. Palpatine instructed him to reach the control room to restore communication. However, Skywalker's communication was interrupted by Alama's arrival. Skywalker employed a mind trick to disorient Alama. As the bounty hunters separated, Skywalker confronted the droid and destroyed it. However, this confirmed to Alama that Skywalker was unarmed. Bane then sent Alama and Sing to rendezvous with Robonino and subdue Skywalker.
Skywalker proceeded toward the control room, but Robonino sealed the door as Skywalker approached. Skywalker attempted a mind trick on Robonino but was held at gunpoint by Alama. He disarmed Alama and held him at gunpoint, but Sing shot the blaster out of Skywalker's hand. Robonino then attacked Skywalker, rendering him unconscious with a shock. They tied him up and brought him before Bane.

Bane contacted Palpatine, instructing him to create a pardon disk and deliver it to Senator Orn Free Taa. 3D then went to the Chancellor's office and escorted Taa to the detention center. There, Ziro was freed and returned to the Senate building. Bane and the other bounty hunters planted bombs around the senators as they prepared to depart. However, as they headed towards the landing platform, Clone Commander Fox's detachment of the Coruscant Guard, summoned by Taa and Palpatine, surrounded Bane's team. Bane refused to surrender, threatening to kill the senators. Consequently, Bane and his bounty hunters were allowed to leave. The senators revived Skywalker, and Amidala returned his lightsaber, claiming he had dropped it. As Bane, his bounty hunters, and Ziro made their escape, Bane detonated the bombs as Ziro's payback. Fortunately, Skywalker created a hole in the floor, saving them before the bombs exploded.

Bane, Ziro, and their associates were pursued by a group of Jedi, with the chase leading into an underworld portal. The spectacle, featuring Jedi leaping between speeders, attracted large crowds. As a diversion, Bane targeted the engine of a transport ship within the portal, causing it to careen out of control towards a crowded landing platform. The Jedi redirected the ship away from the platform, causing it to crash into the side of the portal instead. On the other side of the wall was the home of the Martez family. While their mother and father saw the ship coming, they sacrificed their lives so their daughters, Trace and Rafa, could escape. This diversion allowed Ziro, Bane, and the other bounty hunters to evade capture and disappear into the Coruscant Underworld.

In the immediate aftermath of the crisis, Amidala decided to take a break and traveled with her husband to Risha Synata's ship, only to become involved in a skirmish. Meanwhile, Ziro was taken to Nal Hutta and brought before the Grand Hutt Council at Gardulla's Palace. Aware that they were behind his rescue, Ziro threatened to send the Council records to the Senate if he was killed. Ziro's former lover Sy Snootles aided Ziro in escaping Nal Hutta, but after they traveled to Teth to retrieve the records, Snootles, secretly hired by Jabba, killed him and delivered the holodiary to Tatooine. Bane and Jedi Masters Obi-Wan Kenobi and Quinlan Vos discovered Ziro's corpse, leading to a fight when the Jedi attempted to capture Bane, although the Duros managed to escape.
The Jedi who had pursued Bane returned to the crash site. A female Jedi with green skin and dark robes approached Rafa and told the young woman that she had needed to make a choice about the transport ship, but the Jedi told her not to worry, saying the Force would be with her. The Jedi then left, but both of the sisters were left disillusioned about the Jedi and the view of them as heroes. With the loss of their parents, Rafa instilled a view in her sister that the two of them could only rely on each other. Rafa later recounted the story to Ahsoka Tano, a new friend of Trace's who, unbeknownst to either of them, had been a Padawan before leaving the Jedi Order, while they were imprisoned in the Pyke Palace on Oba Diah.
Although clone troopers had started to see open deployment as law enforcement personnel on Coruscant at the time of the hostage crisis, the failure of Jayfon and his Senate Commandos helped justify the open use of clone troopers on Coruscant itself: Jayfon and his team's failure would be remembered as a blow to trust in the Senate Guard. That their uniforms were then used by Bane's commando droids was a further black mark on the organization. While Senate Commandos had been used as a fast-action military response organization and for additional secruity for the first year and then some of the Clone Wars, they came to lose those duties to clone troopers. In time, clone shock troopers supplanted the Senate Guard, and the Senate Guard was dissolved altogether during the Imperial Era. Sometime before 3 BBY, Bail told his adoptive daughter Leia Organa about the hostage incident.