AS A DEADLY VIRUS STRIKES HOSHI AND TRIP, ALIENS POSSESS VARIOUS MEMBERS OF THE ENTERPRISE CREW TO OBSERVE HOW HUMANS REACT TO A CRISIS, ON "STAR TREK: ENTERPRISE," FRIDAY, JANUARY 21

"Observer Effect" -- After Hoshi and Trip contract a deadly virus while exploring a planet, two ghostly aliens possess the bodies of various Enterprise crew members to observe humanity's reaction to imminent tragedy, on STAR TREK: ENTERPRISE, Friday, January 21 (8:00-9:00 PM, ET/PT) on UPN. Mike Vejar directed the episode written by Judith Reeves-Stevens and Garfield Reeves-Stevens.

As the aliens secretly jump bodies to observe, Phlox strives to cure the stricken pair, but with his efforts failing, Archer must make a difficult decision in order to shield the rest of the crew from this growing biohazard.

Captain Jonathan Archer: Scott Bakula
Chief Engineer Charles Tucker III: Connor Trinneer
Vulcan Sub Commander T'Pol: Jolene Blalock
Lt. Malcolm Reed: Dominic Keating
Ensign Travis Mayweather: Anthony Montgomery
Ensign Hoshi Sato: Linda Park
Dr. Phlox: John Billingsley

RATING: TVPG