|“||For Gerda. Someone had to remember her...avenge her||„|
|~ Carter Greyhorse|
Carter Greyhorse was a human male Starfleet officer and doctor who was the primary antagonist of the Star Trek: The Next Generation novel Reunion.
Greyhorse served from 2333 to 2355 as the chief medical officer of the USS Stargazer under Captain Jean-Luc Picard. Some time after reporting on board he began a romantic relationship with Lieutenant Gerda Asmund, a human female who had been raised by a Klingon warrior and his wife. For over 18 years Gerda and Greyhorse kept their relationship secret from everyone, even Gerda's sister Idun.
After Gerda attempted to kill Ensign Morden, Greyhorse was forced to save her life when she attempted ritual suicide. After she served her sentence in a rehabilitation colony, Greyhorse attempted to resume their relationship, but rehabilitation had changed Gerda and desiring a break with her past, she broke off her relationship with Greyhorse. Gerda later died in a shuttle accident.
The breakup with Gerda and her subsequent death caused a breakdown in Greyhorse. Feeling that her former crewmates had abandoned her, Greyhorse tried to kill them before the crew of the Enterprise stopped him. After he was stopped from killing Captain Picard and the his former Stargazer crewmates, Greyhorse was arrested. Found guilty of his crimes he was sentenced to rehabilitation.
In 2379 he was still undergoing rehabilitation at the New Zealand Penal Settlement when he was recruited to assist Captain Picard rescue Doctor Beverly Crusher, who had been trapped in Romulan space.