We describe the case of a 44-year-old gentleman with hypertension and asthma presenting to the emergency department after noticing right upper-extremity weakness upon awakening. Brain imaging did not reveal a stroke. Initial neurological examination pointed to cervical myelopathy with radiculopathy as well as possible underlying length-dependent peripheral neuropathy as there was right arm strength of 4/5 and there were brisker (3+) reflexes all over except at the right biceps reflex and both ankle reflexes. Cervical spine magnetic resonance imaging (MRI) showed myelomalacia at the C2 level and an os odontoideum (OO). Os odontoideum is a chronic condition that occurs due to the failure of the center of ossification of the dens to fuse with the body of C2. By the next day after a few hours of sustaining a fall, weakness progressed to quadriparesis, without a sensory level on examination, followed by urinary retention. This situation was attributed to a possible cervical cord contusion due to the fall in the presence of OO, with other possibilities being spinal cord hemorrhage, infarct and transverse myelitis. However, repeat scanning of the cervical spine (MRI) did not reveal any acute cord changes. The initial examination for common causes of peripheral neuropathy did not reveal any findings. Finally, the diagnosis of Guillain-Barré syndrome (GBS) was considered, and treatment was initiated with intravenous immunoglobulin. Cerebrospinal fluid analysis was normal. The diagnosis was confirmed using electromyography. Our patient's initial presentation of monoparesis and progression in an asymmetric descending manner was unusual for GBS. His initial presentation mimicked a stroke, and the later progression masqueraded as cervical myelopathy secondary to a chronic cervical cord lesion. The presence of a cervical cord lesion (upper motor neuron) concealed the expected areflexia in GBS. The presence of OO on spine imaging, absence of expected areflexia in GBS, and progression to paraparesis after the fall sidetracked the direction of the initial investigation and led to a relative delay in diagnosis. Nonetheless, appraising the diagnostic data in the clinical context led to an appropriate diagnosis. We emphasize the importance of reconciling the available clinical and diagnostic information to reach the correct diagnosis.