Time Travel is invented in the last decade of the 22nd century, and its inventor, Doctor Mordecai "Mo" Sahmbi, uses it to help criminals escape justice by sending them back 200 years in time. When Sahmbi uses it himself, police Captain Darien Lambert volunteers to go into the past himself, capture the fugitives and return them to the 22nd century to pay for their crimes.
As a more evolved 22nd-century human, Lambert is in better-than-peak physical condition, and possesses a special ability called Time Stalling -- essentially a poor man's Super Speed. He also has access to advanced technology, like a MPPT (Micro Pellet Projection Tube; to all practical effects a stun ray) disguised as a car alarm, and SELMA (Specified Encapsulated Limitless Memory Archive), an artificially intelligent supercomputer the size of a credit card, capable of projecting a holographic avatar in order to better depart and quarrel with Lambert.
The main Phlebotinum of the series are TXP, a drug which allows the "molecular alignment" required for time travel, and TRAX, the time machine which makes time travel possible. (Lambert's MPPT can project pellets loaded with TXP.)
The Time Travel treatment in the series was inconsistent. Captain Lambert, fearing the possible consequences of altering the timeline, did not actively attempt to interfere with the flow of history known to him, although he frequently left messages for his colleagues in 2193 (via the 'personals' sections of a newspaper). However, the series made a couple allusions to a theory of parallel timelines to try (not very succesfully) to evade the issue of temporal paradox, implying that the time travellers went into an alternate past so that their actions there had no effect on the 2193 "present." (This would prevent the newspapers ads to be read in the future, however...) This inconsistency affected the selected method for retrieving fugitives also; after they received a projected pellet, sometimes Lambert published an ad requesting the retrieval, but most of the time SELMA would emit a "transmission tone" which somehow was detected by TRAX and triggered the time travel of the fugitive.
- Bullet Time: Time Stalling
- Disposable Love Interest: Nearly every episode Lambert gets a new girlfriend, then leaves her behind by the time the end credits roll.
- Evil Twin: In the form of a Sahmbi created android in the episode "Almost Human".
- Expositron 9000: SELMA.
- Fantastic Racism: White people are a despised minority in the future, as the planet is united as one country in which Asians and Africans outnumber other ethnic groups. Lambert has been derided with the vicious slur Blanco!.
- Fish Out of Temporal Water: Darien Lambert
- Forgotten Phlebotinum: The transmission tone. Sometimes is not used and Lambert resorts to the old trick of personal ads.
- Human Outside, Alien Inside: The Procardians who appear in one episode have have a number of not-so-obvious biological oddities about them.
- Identical Grandson: Lambert's paramour from the future, Elissa Chang-Knox, and her police grandmother in the present, Annie Knox, who helps Lambert on his initial pursuits.
- Meanwhile in the Future
- Phlebotinum Breakdown: TXP is lethal after two doses; however, the villain from the pilot, Sepp Dietrich, was TXP'd twice before Lambert sends him back to 2193 with a third dose; the effect was not death but failed time travel, deformity and a homicidal rage against Lambert. It's not casual that this happened after the Big Bad, Mordecai Sahmbi, was prematurely confronted and reduced to a mere occasional nuisance.
- Present Day: Darien Lambert's destination
- Product Placement: The opening credits contain a suspiciously long shot of a Continental Airlines airplane in flight; Selma is disguised as an AT&T Credit Card.
- Projected Man: Selma.
- Public Secret Message: Lambert would send messages to the future by placing coded personal ads in the newspaper.
- San Dimas Time: In a couple of episodes.
- Time Machine: TRAX
- Time Police: Averted; only Lambert is chasing the time fugitives, and he's seen as heroic for trying.
- Timey-Wimey Ball: The "parallel universe theory" is mentioned in the pilot, and in an episode which required avoiding a series of assasinations convincing the would-be perpetrators that their actions wouldn't have effect on their own timeline; other episodes acted as if Lambert was changing the timeline with every action.
- And in still other episodes it seemed that some things in his world only exist because he caused them to be - such as looking up his favorite chicken pot pie recipe from a cookbook written in 2192 and giving a copy to the man who invented it in 1992 - thus bringing his favorite meal into existence via paradox.
- There was an episode where Lambert had to save the life of one of his favorite singers. At the end she says she'll name a song after him: Mystery Man. His response? "That's my favorite song".
- In the same episode he tells her she may no longer be famous in her future due to the parallel universe thing. Way to alternate the theories in the same episode.
- US Marshal: Lambert's cover in present day was as a U.S. Marshal, as it is the role of that office to apprehend fugitives.
- We Will Have Perfect Health in the Future: Cancer is mentioned to have been cured by the 22nd century. Additionally, people are generally much healthier and more fit.