In the year 33 BBY, Darth Sidious tasked Darth Maul with a covert operation: penetrating Cog Hive Seven, a notorious prison famous for its clandestine gladiatorial contests where prisoners fought each other. Sidious's directive to Maul was to retrieve a nuclear weapon from Iram Radique, a secluded weaponsmith residing within the prison. Maul's explicit orders were to simply deliver the weapon to the Bando Gora cult, Radique's adversaries; however, Sidious secretly planned to orchestrate events so the bomb would be used in an attempt on the life of his own master, Darth Plagueis, on the moon Sojourn.
Maul's assignment required him to assume a false identity to gain entry into the prison. While undercover, he engaged in a series of deadly gladiatorial combats while simultaneously trying to locate Radique. After securing the nuclear device, he was compelled to collaborate with Komari Vosa, the leader of the Bando Gora, when an attack by Jabba Desilijic Tiure's forces triggered a self-destruct sequence. Despite their initial distrust, Maul and Vosa jointly overcame the Syrox creature and escaped the prison's destruction alongside a young inmate named Eogan Truax. The trio successfully made their way to Hutt Space, after which Maul returned to Coruscant to report back to his master.
At the LiMerge Building located on Coruscant, Darth Sidious gave his apprentice, Darth Maul, instructions to infiltrate the well known Cog Hive Seven prison. The mission was to acquire a nuclear bomb from the isolated weapons designer Iram Radique. Sidious informed Maul that Radique was operating from inside the prison, and the bomb was to be given to Radique's sworn enemy, the Bando Gora cult. Maul was also ordered not to use the Force or reveal himself as a Sith Lord, as it would jeopardize his mission within the prison.
However, Sidious kept the true objective from his apprentice. The primary goal was to manipulate events so the bomb would be used in an attempt to assassinate his own master, Darth Plagueis, on Sojourn. Sidious hoped his pawns would complete the task, sufficiently concealing his own involvement in the scheme.
Maul, using the alias "Jagannath", entered the prison as an undercover inmate and discovered that gladiatorial death matches were held, pitting prisoners against one another. Maul himself had to participate in four of these deadly matches, defeating opponents such as a wild wampa and an Aqualish named Rook, who gave Maul crucial information on locating Radique before his death. Maul also encountered and killed an unidentified warrior, a Yuuzhan Vong, whose species was unknown to him and the prison authorities.
During his mission, he experienced a Force vision where he faced his own dopplegänger. He struck down the apparition, but it then transformed into a Muun with the name "Plagueis" entering his mind before he awoke. (Maul wouldn't understand the true meaning of this vision until later). Darth Plagueis took a keen interest in Maul's mission and dispatched Vesto Slipher, an operative from the IBC, to monitor the Zabrak's progress. Plagueis believed the mission was designed to kill Radique, and to that end, he had Slipher, through Plagueis's droid 11-4D, deliver a geological compressor to Maul to kill Radique with. Slipher was successful but was killed soon after.
The warden of the prison, Sadiki Blirr, learned that the crime lord Jabba Desilijic Tiure had sent undercover agents into the prison. She executed all but one upon discovering this. The Hutt, enraged, retaliated by sending a team to intercept the prison barge Purge to attack the prison. Blirr was forced to respond and activated a self-destruct sequence, but she was killed when the Syrox creature found her in the ensuing chaos.
Maul later formed an alliance with the young inmate Eogan Truax, and together they found Radique and recovered the device. However, Radique betrayed them and refused to help them detach the bombs embedded in their hearts, which all inmates received upon entering the prison. Truax killed Radique, and a wounded Maul (Radique shot him in the right shoulder) managed to summon the Bando Gora using an old code from former cultist Artagan Truax. The Bando Gora's forces arrived, and their leader, Komari Vosa, confronted Maul before engaging him in combat. Vosa didn't realize Maul had summoned her, and their duel ended when the Syrox creature appeared. The pair confronted the creature, and Maul killed it by decapitating it.
The three managed to escape the prison before its destruction and headed for Hutt Space. Maul handed the device over to Vosa. After reaching Hutt Space, Maul returned to Coruscant.
The Bando Gora, along with their allies (including Gardulla Besadii Tai, Ars Veruna, and the Black Sun syndicate), used the bomb to attack Sojourn in an attempt to assassinate Darth Plagueis. However, the Muun received a tip-off and was rescued when Jabba Desilijic Tiure's ship, the Star Jewel, arrived in time. This event also allowed the elder Sith and Sidious to exact revenge on their enemies. Plagueis dealt with Veruna, and Maul was dispatched to exact revenge on the Black Sun. Sidious and Plagueis decided to wait before striking at the Bando Gora, which later happened some months later.