Reviewed by MIKE TOONEY:

“FIELD OF FIRE.” An episode of Star Trek: Deep Space Nine, Season 7, Episode 13 (161st of 173). First airdate: 10 February 1999. Cast: Avery Brooks (Captain Sisko), Rene Auberjonois (Odo), Nicole deBoer (Lieutenant Ezri Dax), Michael Dorn (Lt. Commander Worf), Colm Meaney (Chief O’Brien), Armin Shimerman (Quark), Alexander Siddig (Doctor Bashir), Nana Visitor (Colonel Kira), Art Chudabala (Lt. Hector Ilario), Marty Rackham (Vulcan), Leigh McCloskey (Joran Belar). Writer: Robert Hewitt Wolfe. Director: Tony Dow.

    “I’m sorry, Lieutenant. There’s nothing more annoying than a corpse with a mind of its own.”

   Lieutenant Dax may not look it, but she’s more than one person. Being a Trill, Dax has had a symbiont implanted in her; for better or worse, the symbiont itself possesses all of the memories and skills of every host into which it has been previously introduced. In Dax’s case this turns out to be for the worse, because one of those predecessors was a murderer …

   An interstellar war is raging and millions are dying. The huge space station Deep Space 9, now occupied by hundreds of Starfleet personnel, is serving as a staging area for operations in the war.

   A young Starfleet lieutenant, one who has distinguished himself in combat, is found dead in his quarters, the victim of a bullet fired from a projectile weapon (an antique by 24th century standards) at point blank range — only there are no “powder burns” on the body, the room was locked from the inside, and no one can think of a motive for the crime.

   Later in a fevered dream, Dax unwillingly calls up the forceful but warped personality of Joran Belar, responsible in a previous life for three murders. Reluctantly, she realizes that Joran’s “skills” as a killer could come in handy in the investigation and agrees to let “him” (i.e., the remains of his persona) guide her.

   Soon enough two more murders, both victims serving with Starfleet, occur in the same fashion as the first. Despite Joran’s urgings to think like a killer, Dax is having no luck in her investigation — until an offhand remark from Joran lets her connect the dots, enabling her to locate the murderer. When that moment comes, Dax will have only a few seconds to decide whether she should kill — as Joran is all but screaming at her to do — or be killed …

   In this particular impossible crime mystery, the HOW is discovered fairly soon (and can only have been pulled off in a science fictional scenario); it’s the WHO and the WHY that have everybody flummoxed. For long-time Star Trek fans, the why and the who just might come as something of a shock.

   Tony Dow, who directed this episode, is probably most famous for being the Beaver’s older brother Wally on Leave It to Beaver (1957-63).

NOTE: A transcript of the show (with SPOILERS) is here.