The Cat School settled for a couple years in Hertch where it was funded by King Radowit II of Kaedwen alongside the Wolf School. While trying to cooperate with the other school at first, differing philosophies eventually made Treyse distaste the Wolves and he started looking for a ways to sabotage their position.
In secret, Treyse was approached by Astrogarus, the King's court mage. The sorcerer promised that if the Cats would help in killing off the Wolves, they would take a special place under royal command and monopoly to hunt monsters in his domain. Treyse agreed; unbeknownst to Guxart and a group of more honest students, the Grandmaster recruited Guxart's assistant and the less moral Cat students into the plot. Cats were supposed to strangle unarmed Wolves at the bleachers of the stadium where the first Witcher Tournament was to take place.
Treyse's schemes ultimately turned against him as it turned out that Astrogarus and Radowit played both schools. Once the Cats who took part in the plot started strangling the unsuspecting Wolves, Kaedweni soldiers started to shoot the witchers with crossbows, targeting witchers of both schools. Treyse got shot in chest; not realizing the double treason yet, he yelled that the fools were supposed to shoot the Wolves only. The situation became more clear when Radowit audibly ordered his men to kill all the witchers present; Treyse's life likely did not last much longer.