Twelve-year-old Matthew faces a delicate two-day operation to remove a tumour deep in his mid-brain, next to his pineal gland - a region key to the functioning of sight, muscles, hearing and sensation.
30-year-old Dan and 39-year-old Laura must undergo surgery while remaining awake, allowing the surgeons to map the functioning of their brains. Both their families ask will they be the same people after the surgery is completed?