The syndrome of transient Headache and Neurological Deficits with cerebrospinal fluid (CSF) Lymphocytosis (HaNDL) is classified as secondary headaches attributed to “non-infectious, inflammatory intracranial disease”. The etiology, as well as the pathogenesis of both the headache and the transient focal deficits, remains unknown. A neurologist-on-duty faced with a HaNDL patient in the first hours might erroneously decide to use thrombolytic drugs, a non-innocuous treatment which has no therapeutic effect on this syndrome. Thus, it is important to raise the suspicion and to be aware of this syndrome and the possible diagnosis. A 16 years old boy presented to the emergency room (ER) of Barzilai Medical Center with difficulties in speech due to motor aphasia and severe headache. He first noticed something wrong when he failed to text a message on his phone early that morning. Shortly after he experienced the most painful headache he has ever encountered and was rushed to the ER. Computerized Tomography (CT) and CT angiogram showed no abnormality and no signs of vasoconstriction. Cerebral Spinal Fluid (CSF) showed lymphocytosis 105 cells/microliter, protein 44 mg/dl, and sugar 74 mg/dl (blood145 44 mg/dl). Treatment with IV ceftriaxone 2gX2/d and IV acyclovir 750 mgX3/d was established. The presenting symptoms started to improve a few hours after his admission. CSF cultures and Polymerase Chain Reaction (PCR) for herpes and Varicella Zoster Virus (VZV) were negative. Brain Magnetic Resonance Imaging (MRI) was normal. HaNDL syndrome should be considered as a differential diagnosis for patients presenting with the worst of their life headache, focal neurological deficit and pleocytosis in CSF.