Thrawn's Raid on Coruscant was an operation to kidnap Leia Organa Solo and her twins in order to appease the Dark Jedi Joruus C'baoth. It involved fourteen members of Imperial Intelligence, led by Major Molo Himron. A secondary objective of the mission was to "neutralize" Mara Jade, either by killing or discrediting her.
Joruus C'baoth was impatient at the Noghri Death Commandos' failure at kidnapping Leia Organa Solo and her twins. He demanded that Thrawn launch an immediate attack on Coruscant, so that he could personally capture his quarry. Thrawn refused, stating that the operation wasn't practical, but mentioned that a commando raid would be feasible. This kidnapping attempt was different from the others in two ways. One, Leia had given birth to the twins, meaning that they were guaranteed to be on Coruscant for the time being, and two, the Noghri would not be involved.
Thrawn handpicked a team of fourteen Imperial Intelligence commandos led by Major Himron. After personally planning the operation, seemingly thinking of every variable, he instructed the team to discredit Mara Jade, rather than killing her. Major Himron also planned to take a bit longer to reach Coruscant to leave a realistic trail on their transport.
The evening of the raid coincided with the Sarkan reception in the Palace. The commando team infiltrated the Palace using a private entrance, and quickly impersonated a Security team. They set up comlink jamming, and moved to enter the Solo's quarters using an electronic lock-pick. All might have succeeded if it wasn't for one person - Mara Jade.
Mara Jade, sensing danger, left her quarters to see four of the commando team's members walk down the corridor. Mara recognized the bent diamond formation and the hand signal of the team as Imperial standards and tried to follow them. She was stopped by Lando Calrissian and Garm Bel Iblis, who had noticed the comlink jamming and were investigating. Mara Jade quickly explained the situation, and Lando went to get his blaster. Jade sent a message to Leia through the Force in order to wake her up.
Leia, hearing Mara Jade's message, woke up to hear the hum of the electronic lockbreaker. She reacted by shooting the wooden door, allowing the secondary metal security door to activate. Han and Winter woke up and decided to buy some time by moving into Winter's room, so the commandos would have to search both rooms instead of one. They barricaded the room while a firefight raged outside.
Lando, Jade and Bel Iblis were surprised by the team's rear guard and began shooting. Lando had the idea of using the Millennium Falcon to rescue the Solo's from the window and went down to the hangar. Meanwhile, Palace Security arrived and brought an E-web to quickly eliminate the team. Unfortunately, it wouldn't get there fast enough before the commando's would have hostages. Mara Jade, using her knowledge of the Emperor's hidden passages, decided to ambush the commando's from a different direction. She killed several commandos before sending a second message through the Force, telling Leia to surrender.
Meanwhile, inside the rooms, Leia decided to use her lightsaber to exit via a wall. Han wasn't sure that it would work as Thrawn probably had already guessed that they would try that. Leia, saying that Thrawn was not infallible, got ready to go through the window. At this point, the Millennium Falcon was outside and began sending a signal, which C-3PO identified as a gambler's code. Not knowing if it was a trap or not, Leia began to cut through the window when the team finally broke in the door. Leia heard the message and surrendered. Her surrender created a pause in the fight while the commandos moved to apprehend her. This allowed Mara Jade to quickly kill the remaining members of the team from behind.
The entire team, save Major Himron, was killed, but Himron had one more move. He identified Mara Jade as the person who let them into the Palace, thus discrediting her in front of the New Republic leadership. Unfortunately several people, Leia included, did not believe him.
After hearing of the news, Joruus C'baoth once again demanded an attack on Coruscant, to which Thrawn agreed this time. In the end, Thrawn had made one of his few, but crucial mistakes. By not killing Mara Jade, she would end up leading the New Republic to Wayland and ending the war.