|Episode no.|| Season 3|
|Written by||Tony Blake, Paul Jackson|
|Directed by||Richard Compton|
|Original airdate||September 27, 1996|
|List of Sliders episodes|
Double Cross is the first produced, but the second aired, episode for the third season of the science fiction television show Sliders. On a world with dwindling natural resources, Professor Arturo, Quinn, Rembrandt, and Wade are offered the technology needed to send them home, for a price.
The Sliders arrive in a dark tunnel with an express train bearing down on them. Seconds before impact, the train stops and a computer voice announces that Sector 47 will resume power in 30 minutes. Arturo, Quinn, Rembrandt, and Wade come out of the tunnel and find themselves in San Angeles, a megalopolis that stretches from Los Angeles to San Francisco. Frequent power brownouts, gasoline at $410 per gallon, and a nutrient paste called "Geomash" are just three items on this world as a result of dwindling natural resources. Shortly after emerging from the tunnel, a woman named Monique drives up beside Rembrandt and claims to be his biggest fan. He goes off with her, and then Arturo, Rembrandt, and Wade are pursued by security guards on motorcycles. After they're cornered, one of the riders removes her helmet and identifies herself as Logan St. Clair, a researcher at Prototronics who discovered their sliding vortex and wants their help perfecting their own. In return, she's willing to help them get to their home Earth.
As Arturo, Logan, Quinn, and Wade pass through Prototronics' thermal scan, it's discovered that Quinn and Logan's patterns are identical—they're doubles of each other. While Quinn, the original developer of sliding technology, works with Logan, Arturo and Wade become suspicious of the time they're spending together and return to the Dominion Hotel, a five-star establishment on this world. When the maître d'hôtel greets Arturo, mistaking him for his double, and asks why his other ladyfriend is not with him, he pieces together that his double was previously here with Logan St. Clair. Arturo was also married on this world, and he later finds from his double's widow that he supposedly tested their vortex himself through his impatience and died due to its instability.
After a dubious lunch consisting of frog sweetbreads, Monique and Rembrandt go to her mountaintop home to relax. Hours later, Rembrandt finds a shrine to his double, a famous entertainer on this world, and confronts Monique about it. She's wearing a wedding dress and wants to marry Rembrandt in a fulfillment of her celebrity stalking fantasy. At that moment, Monique's fiancé Michael comes inside and threatens to kill Rembrandt, who flees and returns to Sector 47 on top of a bullet train.
Logan and Quinn exchange information about the respective technologies they're using; Logan then conducts a "power test", opening a high-powered vortex that pulls them both off their feet. The power is cut before any damage is done, but Quinn comments that Logan could have sent a convoy through there. She tries to convince Quinn to stay during an evening walk by the Golden Gate Bridge.
At Prototronics headquarters, Wade finds out from their security footage records that Logan shoved Arturo into their unstable vortex after he learned what they really intended to use sliding for - to rob other worlds of their natural resources and "hold the world hostage." Wade is kidnapped by a Prototronics guards whilst Arturo is searching his double's apartment. An actress hired to impersonate Wade meets Arturo, but she gives herself away when the pair return to Prototronics to talk to Arturo's double's late wife, and she says he ought to know about sliding because he was the one who invented it. Having tied up the rogue Wade double, and meeting with Quinn, they decide to find a video disk, mentioned by Mrs. Arturo, and use it as a bargaining chip to free their Wade. With this in their possession, Logan catches them and explains she knows what Quinn will do since she is his double; in a struggle, Arturo is pushed through an unstable vortex, but returns to free Quinn and Wade from the headquarters after the computer program finds this world's co-ordinates Logan so desperately needed, and deposits him a little later in the same place he was pushed into the vortex. Quinn's computer virus then erases the co-ordinates, destroying any help they may have given Logan.
They meet Rembrandt at the Dominion Hotel with Logan on their heels and get through the door just as a brownout is declared for the next fifteen minutes. Arturo gives proof of Prototronics' scheme to the maitre d' to give to his wife as she'll know what to do with it, and they slide out.
Arturo, Quinn, Rembrandt, and Wade arrive in a hotel bar in "Lotusland". After being met by the Jamaican-sounding Elston Diggs, Quinn discovers that Logan switched the geographic spectrum stabilisers between their timer and her own. From this point on, they'll land anywhere in a 400 mile range between San Francisco and Los Angeles. Logan St. Clair appears in a vortex behind them, and demands at gunpoint that they fix her timer so she can return to San Angeles. Quinn agrees, but he instead enters a new set of coordinates so she's sliding at random now as well. However, since she had the technology to track wormholes courtesy of Prototronics, it's possible they'll meet her again.
- When Logan St. Clair tells Arturo that his double was impatient to slide and having attempted to without perfecting the safety protocols, he remarks in response, "He did? How odd!?", implying this is the Arturo from the world that stayed behind and fought the original Arturo prior to one of them being knocked unconscious. His reaction to her comment indicates this might be the case. Conversely, a short time later, Arturo relates to Quinn that he doesn't believe his double would slide without first testing with a probe. This doesn't necessarily mean this Arturo is the original, simply that he's prudent and cautious, something the alternate world Arturo definitely was.
- Quinn explains to Logan after she remarks disbelief at their 2 year period of sliding that he had opened the vortex on another dimension before the timer reached zero, this early access corrupted the program, resulting in the erasure of their home dimension's coordinates.