When they enter institutions of higher education, students typically leave behind one culture to join another. Despite the higher rates of attrition for first-generation students over continuing-generation students and undecided students over declared students, little research has been focused on undeclared first-generation students. To understand the challenges and experiences of first-generation undecided students transitioning to a new and unfamiliar academic environment, we applied a reacculturation process to this qualitative exploratory case study of 35 students. Data came from interviews, focus group interactions, observations, and written responses to open-ended questions, which were subsequently triangulated. Findings revealed heightened feelings of stress, desire to become comfortable on campus, reliance upon continuing-generation friends, helpfulness of a specialized first-year seminar course, and uncertainty about advisors' roles.