A young man presented with recent-onset non-specific symptoms like headache, sleepiness and weight loss, interfering with normal daily life. Physical and biochemical irregularities were absent. Because extensive examination by neurologist and psychiatrist including brain imaging did not reveal any clues, the complaints were initially considered psychosomatic. As the symptoms deteriorated with ongoing weight loss, the patient was re-admitted to the hospital. Again, extensive additional investigation did not reveal any abnormalities. Because of previous exposition to the woods Lyme serology was determined. Surprisingly, it appeared to be a remarkable presentation of acute Lyme neuroborreliosis which was successfully treated with ceftriaxon. Clinicians must be aware of the fact that this severe illness can present without any typical symptoms.