A 30-year-old female patient with a past medical history of pernicious anaemia presented with pleuritic chest pain, palpitations, fatigue, coryzal symptoms and a high temperature. She was hypoxic and tachycardic and was extensively investigated as well as aggressively treated. A type 1 'gut feeling' assessment by the admitting medical registrar made the diagnosis possible as thyroid function tests were grossly deranged and pointed to Graves' disease causing heart failure, complicated by pneumonia. The patient was discharged on carbimazole, antibiotics and beta blockers. Due to a resultant thrombocytopaenia, she has now been swapped onto propylthiouracil and is under active follow up.