The Battle of Sector 90 occurred when Captain John Sheridan decided to test the theory that telepaths could be used as weapons against the seemingly unstoppable Shadow vessels. To this end, he asked the rogue telepath Lyta Alexander to join him on a mission against the Shadows. He took the White Star into hyperspace to wait for word of a Shadow attack. A single Minbari cruiser provided escort.
When word came of a Shadow attack in Sector 90 by 110 by 47, Sheridan's White Star entered normal space, leaving the Minbari cruiser behind in reserve. In Sector 90, they found a single Shadow vessel causing havoc. Lyta's initial attempts to freeze the Shadow ship were unsuccessful. However, when she learned exactly what the Shadows had done to Kosh, she became enraged and unleashed her full telepathic power upon the enemy vessel. The Shadow vessel froze, allowing the White Star to destroy it with a single concentrated burst from is neutron cannon, though much of the ship's energy was used up in the process.
Unfortunately, the Shadow ship managed to send out a distress call before it was destroyed. Soon enough, four more Shadow vessels materialized and began chasing after the White Star, which couldn't jump because its engines were recharging. The Minbari cruiser exited hyperspace to assist. The Minbari telepaths on board the warcruiser jammed three of the Shadow vessels, but the fourth one slipped through and caught up to the White Star.
Just as it looked like the Shadow ship was going to destroy the White Star, a Jump point opened and the G'Tok appeared. Catching the Shadow vessel off guard, it blasted the enemy ship with its twin laser cannons, stunning it. The White Star turned around and fired upon the Shadow vessel as well. The combined firepower of the White Star and the G'Tok made short work of the Shadow ship.
Moments later, a fleet of ships from the League of Non-Aligned Worlds led by G'Kar exited hyperspace. Outnumbered and faced with the power of the telepaths, the remaining three Shadow vessels fled.