A dying scientist transfers his consciousness into Data.
The Enterprise answers a call from Dr. Ira Graves, a brilliant scientist and one of the great minds of the age, who is dying and has little time left. Data admires him greatly and is delighted to meet him. Soon afterward Graves dies, but Data begins behaving strangely, with a new arrogance and a harsh manner.
It turns out the scientist transferred his mind into the android's body, and Data's own personality is being suppressed. The story is a fine showcase for the android's range and gives Dr. Pulaski a chance to be sharp in a medical emergency. The episode raises questions about the nature of consciousness, mortality and the ethics of using another being as a vessel for one's own survival.