The Raid on Pantolomin took place during the Thrawn campaign. It allowed Grand Admiral Thrawn to gain the location of the mythical Katana fleet.
In 9 ABY, Han Solo and Lando Calrissian visited the Coral Vanda while searching for information about the Katana fleet. They wanted to meet Captain Hoffner who discovered the fleet years before.
But the Imperial Intelligence had also discovered the identity of Hoffner and Grand Admiral Thrawn had sent Niles Ferrier to capture him.
Han Solo and Lando Calrissian didn't meet Hoffner because Ferrier and his mercenaries had already caught him. Solo and Calrissian tried to free him but the Coral Vanda was forced to surface and surrender due to the turbolaser bombardment of the Chimaera. Stormtroopers immediately boarded the ship forcing Solo and Calrissian to escape in an escape craft.
Niles Ferrier delivered Hoffner to Grand Admiral Thrawn who was able to convince, financially to not lose time, the captain to give him the coordinates of the Katana fleet.
Talon Karrde later gave the coordinates to the New Republic in order to avoid the Empire to retrieve the fleet. However, due to political discussions in the New Republic Provisional Council, the New Republic Navy was too slow to stop Thrawn. Thrawn eventually managed to secure almost all the fleet.
- The Complete Star Wars Encyclopedia