Unilateral absence of pulmonary artery is a rare congenital abnormality that occurs due to malformation of the sixth aortic arch during embryonic development. The clinical presentation of unilateral absence of pulmonary artery can vary based on age of diagnosis; however, in the adult population, it can present with a variety of manifestations including hemoptysis, recurrent pneumonia, and pulmonary hypertension or as an incidental finding. Diagnosis and management of unilateral absence of pulmonary artery remain a challenge. Here, we describe a case of a 37-year-old female with no known past medical history who presented with progressively worsening dyspnea and fatigue. She was incidentally found to have unilateral absence of pulmonary artery on computerized tomography angiography of the chest. Her imaging and physical exam demonstrated signs of volume overload and severe pulmonary hypertension. She received diuretics with good response and was discharged with referral to pulmonary hypertension clinic and eventual follow-up with right heart catheterization. In summary, we describe a rare congenital condition and highlight its diagnostic and therapeutic challenges.