Despite working at the headquarters, Juliana was unaware of ExoGeni's real interest on Feros, namely the Thorian and its mind-controlling abilities. Juliana hid with other survivors on the Skyway after the geth attacked Feros, but was separated from Lizbeth. She and Ethan Jeong became the de facto leaders of the survivors there, with Juliana acting as the voice of morality and reason in contrast to Jeong's expedient focus on ExoGeni's interests. Juliana asks Commander Shepard to look for her daughter when the squad goes to the geth base.
During Shepard's absence, communications are restored and Juliana discovers that ExoGeni is planning to purge the colony. She tries to send a transmission asking for help, but Jeong forces her away from the radio and has her restrained, just as Shepard arrives back. After Jeong has been dealt with, Juliana is shocked to hear about the Thorian but quickly grasps the situation. She offers Shepard the chance to incapacitate the colonists at Zhu's Hope using Thorian-specific nerve gas grenades.
Later, Juliana can be found at Zhu's Hope with Lizbeth. She explains ExoGeni's reaction to the events on Feros.