One of the most intriguing stories and characters in Star Trek is that of The Next Generation’s season 6 episode “Second Chances” and Will Riker’s transporter double twin brother, Thomas Riker.
Thomas Riker was the result of a transporter accident in 2361 that created two William Thomas Riker’s, genetically indistinguishable from each other, with personality and memories identical up to the point of the duplication. Thomas, Using Will’s middle name to distinguish himself from the other, was found on Nervala IV 8 years after the accident occurred.
In 2361, William Riker, at the time a lieutenant assigned to the USS Potemkin, was leading an evacuation mission on the planet Nervala IV. The planet was notorious for its atmospheric distortion field which prevented the use of transporters and shuttles except for brief periods every eight years. During Riker’s transport from the planet’s surface, a second confinement beam was initiated to overcome these difficulties, with the intent of reintegrating the two beams in the transporter buffer prior to rematerialization on the ship. However, the modulation of the distortion field caused only one transporter signal to correctly materialize on the Potemkin – the second signal bounced off of the field and rematerialized on the planet’s surface, unbeknownst to the rest of the crew. As a result, two identical William Thomas Rikers were created. One materialized aboard the Potemkin, and the other was left on the planet’s surface, his existence going unnoticed by the crew of the Potemkin. Because the split between signals resulted in an equal distribution of Riker’s transporter pattern, both of them had an equally legitimate claim to being the “real” William T. Riker.
8 years later, the USS Enterprise-D returned to Nervala IV to retrieve equipment left behind from that evacuation. Thomas was beamed aboard the Enterprise and immediately, he and Will clashed due to resentment they felt for each other. Will had been promoted to Commander because of his actions during the original mission while Thomas was left behind to survive on his own, thinking he was the only true William Riker, and the shock of discovering he was a duplicate.
As the years passed for Will, and after receiving his promotion, he chose to concentrate on his career, which meant his relationship with Deanna Troi was ended. Thomas however, was spurred on with his fight for survival with thoughts of maybe seeing Deanna again, never losing his love for her. Once on board the Enterprise, he tried to revive this relationship. Skepical at first, Deanna tried to let Thomas down, but eventually she gave in to his advances and the two became involved once more.
As time moved on, Thomas realised he had no place on the Enterprise, his competition with his brother, a superior officer, was just too much. Captain Picard arranged a posting aboard the USS Gandhi and Thomas wanted Troi to leave the Enterprise with him. Their new found love was not strong enough for Deanna to want to leave the Enterprise, so she refused his offer. William, who had gotten used to the idea of a second “him” gave Thomas the parting gift of his trombone.
While aboard the Gandhi, Thomas began to sympathise with the Maquis cause, Federation citizens living in Cardassian territory, dismayed at the Federation’s policies towards the Cardassians and the Federation colonies in the Demilitarized Zone, and later joined the Maquis resistance. In 2371, Thomas resumed the identity of William and boarded station Deep Space Nine. He became friendly with Major Kira and managed to convince her of letting him have a tour of the newly commissioned starship USS Defiant. Once on board, Kira, having no reason to distrust Commander Riker, deactivated the ships security lock outs, and just as she did, recieved a phaser blast from Thomas.
Thomas set-up a fake warp core imbalance and instructed Commander Sisko to release the docking clamps so he could move the ship to a safe distance and then be beamed off the ship, but as Sisko released the clamps, the Defiant entered warp and disappeared.
Now with other Maquis members on board, Thomas took the Defiant to the Orias system, deep in Cardassian space, where the Maquis believed that the Cardassians were building a fleet of warships. Major Kira accused Thomas of still acting like a Starfleet officer instead of a terrorist; more concerned with intelligence reports and interstellar politics than with simply hurting the enemy. Trying to locate the Defiant with the assistance of Commander Sisko, Gul Dukat swore that he knew nothing of the fleet in the Orias system. He was telling the truth, as the fleet had been constructed by the Obsidian Order in direct violation of Cardassian law. As the Defiant arrived at Orias, it was intercepted by a number of Cardassian warships.
Sisko achieved a compromise with Dukat and negotiated Thomas’ surrender – in exchange for the Defiant’s sensor scans of the secretive Orias base, Thomas’ sentence would be reduced to life imprisonment in a labor camp on Lazon II, while the Defiant would be escorted back to the Federation-Cardassian border returning the rest of the Maquis crew to the Federation for trial. Thomas was initially wary of accepting the terms offered to him, but Kira pointed out that it would accomplish his mission and let his crew escape Cardassian imprisonment, even challenging his reluctance as some kind of death wish, a desire to go out in a blaze of glory in order to distinguish himself from the other, more successful William Riker.
Immediately after Thomas surrendered the Defiant to the Galor-class cruisers of the Cardassian Central Command, the Kraxon extended its shields around the Defiant to protect her from the fast approaching ships from Orias (upgraded Keldon class cruisers with markedly higher top speeds than regular ships of its class). Upon seeing this, the ships from Orias – under the command of the Obsidian Order and not technically part of the Cardassian military – turned around and returned to the Orias system.
Just before Thomas transported over to the Kraxon, Kira promised to return for him one day, but it is not known whether she ever did.