The Enterprise answers a distress call from Gravesworld. Dying scientist Dr. Graves transfers his mind and knowledge into Data and takes over his personality.

Diana Muldaur (Dr. Katherine Pulaski)
W. Morgan Sheppard (Dr. Ira Graves)
Susie Plakson (Lieutenant Selar)
Barabra Alyn Woods (Kareen Brianon)

• Data tries to grow a beard at the beginning of the episode.
  
• Dr. Graves claims to have taught Data's creator, Dr. Soong, everything he knew. In effect, he is the father of Soong's work and asks Data to call him "Grandpa."
  
• This episode marks the only on-screen appearance by the Vulcan physician Dr. Selar, though she is mentioned by name several times throughout the series.
  
• The Enterprise has to leave to answer a distress call from the U.S.S. Constantinople, which is why Dr. Selar was on the away team in place of Dr. Pulaski.
  
• Susie Plakson (Dr. Selar) will go onto play Ambassador K'Ehleyr in "The Emissary".