Prior to the attack on the Sempre, a large espionage operation was conducted by members of the Higher Skies Advocacy Group and Yinchom Dojo on the galactic capital of Coruscant. This operation involved collecting information on Imperial projects and targets on behalf of the insurgent leader Nevil Cygni, who harried the Galactic Empire. This spy network was exposed by the Lothalite expatriate Arihnda Pryce, who became a double agent under the guidance of Commander Thrawn and the Head of the Imperial Security Bureau Colonel Wullf Yularen. As a reward for her services, Pryce was made Governor of the Lothal sector by Grand Moff Wilhuff Tarkin.
Students sparring at the Yincholm Dojo
Under the advice of the mysterious Nightswan, Driller MarDapp of Higher Skies instructed employees, including his friend Arihnda Pryce, to create political connections of high-ranking Imperial government officials and use data-thief programs on their computers to steal valuable information. The information would then be used to blackmail the officials. Meanwhile, Juahir Madras and other members of the Yinchom Dojo, who trained bodyguards of Imperial senators and other officials, blackmailed them in order to turn them into spies for the dojo. The spying operations eventually resulted in an attempted assassination of Senator Evidorn.
While Colonel Wullf Yularen and Captain Thrawn conducted an investigation to uncover the identity and motivations of Nightswan, they eventually were led to Yinchom Dojo after Thrawn discovered that Nightswan was involved in several political protests, including one in Nubia. Following this thread, Yularen and Thrawn were able to deduce that political upsets would be effective if they began in training dojos, leading them to Yinchom Dojo with Thrawn discovering that the dojo may be part of a conspiracy and was involved with Higher Skies. They got their chance to investigate both when Moff Ghadi tried to blackmail Pryce into spying on the group for him. Because Ghadi had pulled a similar trick on her before, Pryce went straight to now Commander Thrawn. Per Thrawn's advice, Pryce decided to turn on her friends and employer in return for immunity and enlist the support of Grand Moff Wilhuff Tarkin. Under Thrawn and Yularen's direction, she copied the database of Higher Skies.
Pryce has Juahir arrested
Using the information obtained and her secret recordings of Moff Ghadi, a political rival of Grand Moff Wilhuff Tarkin, Pryce was able to bargain the information for the title of Acting Governor, and in one or two years, gain the permanent title of Governor of the Lothal sector. As a favor to Thrawn, Pryce convinced the Grand Moff to promote his friend Ensign Eli Vanto, who had been denied a promotion through Ghadi's machinations. Pryce returned to meet her former friend, Juahir, and with the help of Yularen, arrested her. At the same time, ISB agents and officers arrested other members of Yinchom Dojo and Higher Skies, including Driller. Since Thrawn had ascertained that the Yinchom Dojo's Togorian owner H'sishi was not involved, she was spared.
The disruption of the Imperial espionage operation dealt a blow to Nightswan's campaign against the Empire. As a reward for her services, Pryce was appointed Governor of Lothal. After a year of training, she returned to Lothal and presided over the expansion of Imperial industrial projects, mining, and military facilities on the pastoral Outer Rim world. In addition, Grand Moff Tarkin arranged for Thrawn to be promoted to Commodore and Vanto to be promoted to Lieutenant Commander. Pryce and Thrawn's partnership to disrupt the spy ring led to the formation of a durable alliance between the Governor and promising Imperial Navy officer.
Meanwhile, Pryce's former friend Juahir was imprisoned at the Oovo Four detention center. While Juahir had been spared the death penalty, she had been sentenced to imprisonment. Knowing that Pryce had become Governor of Lothal, she wrote twenty messages petitioning Pryce to help her. Still bitter over her friend for "exploiting" her, Pryce ignored those messages.
The Imperial espionage operation first appeared in Timothy Zahn's 2017 novel Thrawn, which serves as a rebooted Canon origins story for the titular character. The espionage operation serves as a plot element to explain the tritagonist Arihnda Pryce's rise to the Governorship of Lothal, linking the novel to the animated Disney XD television series Star Wars Rebels.