After being betrayed by her lover Vilgefortz, Tissaia feels partially responsible for the death and destruction of her fellow mages and Aretuza. Yennefer has managed to bring together the remaining mages and wants to devise a plan to fight back against Nilfgaard and the elves. But, Tissaia in her weakened state seemingly wants to give up.

Yennefer has a pep talk with her telling her that she is the strongest sorceress and that the other girls (especially Yennefer) need Tissaia to lead them and need her strength.

In the Season 3 finale, Tissaia writes Yennefer a goodbye letter, referencing their first magic lesson. "Sometimes a flower is just a flower, and the best thing it can do to us is to die," Tissaia says while holding a flower and levitating a rock, which makes the flower die. This lesson is showing that the strong will be lifted up and "ascend" while the flowers will simply act as a conduit for magic and die off after they've served their purpose.

It seems Tissaia feels she has served her purpose and it's time for a new leader to rise up and take charge of the mages, and that person is Yennefer.

The series concludes with Yennefer and the other mages finding Tissaia's lifeless body. Though Yennefer is devastated by the loss of her "mother," she knows that she must lead the other sorceresses in the upcoming battles.