Overview:Dr. Black's team of fourth year medical students try to determine why a young nanny is suffering from hallucinations of her head exploding. Will and Catherine struggle to get their relationship back on track after she reveals that she cheated on him during a manic episode? After the chief of neurosurgery suffers a seizure during surgery, the Cube’s medical director calls a meeting to announce that any doctors suffering from medical conditions that could harm patients must come forward.