Pulmonic and sub-pulmonic valve endocarditis are rarely encountered in clinical practice. We present the first case of isolated sub-pulmonic endocarditis. A 30-year-old man with a history of mechanical aortic valve presented to the emergency department with multiple complaints including nausea, vomiting, body aches, and fevers. The patient underwent surgical resection for sub-aortic stenosis followed by a modified Konno procedure later in life. A modified basal short-axis view on the trans-thoracic echocardiogram revealed a sub-pulmonic mobile structure highly suggestive of infective endocarditis. Blood cultures grew methicillin-sensitive Staphylococcus aureus within 24 hours. Higher oxygen demand prompted chest imaging, chest CT showed the development of bilateral airspace consolidation, suggestive of pneumonia. After treatment with extended intravenous antibiotics, follow-up echocardiogram four months later showed no identifiable sub-pulmonic vegetation. This case describes a situation where clinicians may suspect infective endocarditis in a typical location such as a mechanical aortic valve. However, in patients who develop pneumonia, infective endocarditis of the right heart should be suspected. The pulmonic valve and sub-pulmonic ridge are often difficult to image given their anatomical location, a modified basal short-axis view on trans-thoracic echocardiogram can better image these structures.