To improve his performance as the ship's physician, The Doctor undertakes a personality enhancement project on the Holodeck, incorporating several accomplished historical figures' traits and temperaments into his Starfleet database. But he also adopts several aberrant character traits from those non-fictional figures and is soon over taken by a dangerous, cruel Mister Hyde-like personality.

David Lee Smith (Zahir)
Stephen Davies (Nakahn)
Noel de Souza (Ghandi)
Christopher Clarke (Lord Byron)
Sue Henley (Ensign Brooks)