Episode 192: "Identity Crisis" 

Geordi's friend and former shipmate, Susanna Leijten, informs him that the two of them are the only crew members remaining from an Away Team that once investigated the mysterious disappearance of several people on the planet Tarchannen III. The last of their former colleagues has stolen a shuttlecraft to head back to the planet, and Susanna enlists the U.S.S. Enterprise's aid to find out what is happening. The starship follows the shuttlecraft to the planet discovering two additional shuttlecrafts on the surface, but no life signs. After Geordi finds two torn Starfleet uniforms, Susanna tells him she senses the presence of the others and heads off into the darkness. When Geordi tries to stop her, she begins thrashing like a wild animal. He has her beamed to Sickbay.
Dr. Crusher finds that Susanna's blood chemistry has been altered, and Geordi notices that her hands shake uncontrollably. Susanna realizes that whatever happened to the other Away Team members is happening to her and could soon happen to Geordi. Confined to the starship so that Dr. Crusher can observe and treat her, Susanna begins to feel confined, and eventually rushes off to escape the ship. Before she can, however, she collapses. Geordi runs to her, discovering that her skin is covered with dark blotches and her two middle fingers have fused together.

Based on her examination of Susanna, Dr. Crusher determines that the people who disappeared from Tarchannen III were not abducted, but transformed into another species. While Beverly searches for the cause of Susanna's transformation, Picard issues an order that Geordi's every move be monitored by computer in case he should also be motivated to leave the ship. Geordi spends his time aboard ship painstakingly reviewing a visual recording made five years ago at the scene of the original investigation.

While reviewing the tape, Geordi notices a shadow that has no known origin. He recreates the entire scene in the Holodeck, determining that an unknown creature was present on the planet during the fateful Away Team mission. Moments later he is struck with a sudden pain, and looks down to see that his two middle fingers have fused together. Meanwhile, Dr. Crusher locates and removes the parasite responsible for Susanna's transformation. Hoping to scan Geordi for the parasite before it affects him, Dr. Crusher summons Geordi, but a security team discovers his torn uniform and sees a half-alien Geordi overcome a transporter technician and beam to Tarchannen III. Susanna insists on accompanying the Away Team on their search for Geordi, insisting that what she has gone through will help her find him. She is allowed to go, and finds him almost completely transformed. However, she is able to appeal to his human side and talk him into returning to the starship, where he undergoes surgery and regains his human identity.

Production: 192
Season: 4 Episode: 18
Air Date: 03.25.1991
Stardate: 44664.5
Patrick Stewart as Jean-Luc Picard
Jonathan Frakes as William Riker
Brent Spiner as Data
LeVar Burton as Geordi La Forge
Michael Dorn as Worf
Gates McFadden as Beverly Crusher
Marina Sirtis as Deanna Troi
Patti Yasutake as Nurse Ogawa
Maryann Plunkett as Susanna Leijten
Amick Byram as Hickman
Mona Grudt as Ensign Graham
Dennis Madalone as Transporter Chief Hedwek
Paul Tompkins as Breville
Radio Personalities Brian Phelps and Mark Thompson make an uncredited appearance as two of the aliens in this episode. This was also cross featured as an episode of their television show "The Adventures of Mark and Brian" that took the viewer behind the scenes of ST:TNG.

Click this link to view the complete script in a TXT format

STAR TREK: THE NEXT GENERATION 
                       "Identity Crisis" 
                          #40274-192 
                          Teleplay by 
                         Brannon Braga 
                           Directed 
                          Rick Kolbe 
THE WRITING CREDITS MAY NOT BE FINAL AND SHOULD NOT BE USED
FOR PUBLICITY OR ADVERTISING PURPOSES WITHOUT FIRST CHECKING
WITH THE TELEVISION LEGAL DEPARTMENT.
Copyright 1991 Paramount Pictures Corporation. All Rights
Reserved. This script is not for publication or
reproduction. No one is authorized to dispose of same. If
lost or destroyed, please notify the Script Department.
                         FINAL DRAFT
         STAR TREK: "Identity Crisis" - 1/11/91 - CAST 
                STAR TREK: THE NEXT GENERATION 
                       "Identity Crisis" 
                             CAST                               
                PICARD             SUSANNA LEIJTEN
                RIKER              HICKMAN
                DATA               BREVELLE
                BEVERLY            
                GEORDI             Non-Speaking
                WORF                 TWO ALIENS
                                     MENDEZ
                TRANSPORTER CHIEF HEDRICK
                NURSE ALYSSA OGAWA 
                ENSIGN GRAHAM      
                COMPUTER VOICE    
 
                Non-Speaking       
                  SUPERNUMERARIES    
                  SECURITY GUARDS    

Click this link to view the complete script in a TXT format