The Syndrome of Trephined (SoT), also known as, "sinking skin flap syndrome," is a rare neurological complication that can occur after craniectomy. It can manifest with various reversible neurological symptoms such as headaches, mood changes, cognitive impairment, and focal neurological signs. The underlying pathophysiology of SoT is not completely understood but is believed to result from changes in intracranial and cerebrospinal fluid dynamics due to the loss of the protective cranial enclosure following craniectomy. Despite its rarity, healthcare providers should consider SoT as a possible diagnosis in patients who develop neurological deficits after undergoing decompressive craniectomy, even if their symptoms are unusual. In this case, we describe a 61-year-old male who presented with excessive somnolence following a right hemicraniectomy after a head strike with a resulting frontal hematoma and subarachnoid hemorrhage. Imaging evaluation revealed reduced intracranial pressure and a subtle mass effect on the right frontal lobe, resulting in a 6 mm midline shift to the left. After undergoing cranioplasty, the patient's neurological status markedly improved. Our case underscores the importance of recognizing the diverse manifestations of SoT for prompt diagnosis and management. Additionally, it highlights the potential advantages of early cranioplasty in improving neurological symptoms.