Reesa is grateful that the dead have been put to rest, and wants to give herself to restore the Starved Plain. She proposes a sacrifice of herself and her students that will allow plants to grow again on the plain. Reesa asks the Vestige to seek out a mushroom, Kwama Cap, from a kwama nest nearby.
Head to the cave (follow the compass marker). The Vestige will find the Kwama Cap a short distance inside the cave. When they obtain the mushroom, the Kwama in the cave and in the vicinity will become hostile.