Star Trek: Legacy

Single player
The three eras of Star Trek: Enterprise, The Original Series and The Next Generation make up the single-player campaign. In each era, the player utilizes a fleet of Federation ships from that era as the Federation goes up against the Romulans, Klingons, and the Borg Collective. The Next Generation era includes material from Deep Space Nine, Voyager, and the Next Generation movies.

An article on Eurogamer, posted on 7 August 2006, revealed that Derek Chester has collaborated with original Star Trek writer D.C. Fontana on the scripts of Star Trek: Legacy and Star Trek: Tactical Assault. Fontana and Chester gave an interview on IGN, posted 29 November 2006, in which they revealed that the storyline incorporates the split between the Vulcan and Romulan races, known as the Sundering.

The Enterprise Era
Episode I: Those in Need

The story begins with the player taking the role of Captain Jonathan Archer approximately four years after the conclusion of events in the Star Trek Enterprise television series. He is ordered by Starfleet to search for a missing Vulcan scientist in a nearby star system. The Enterprise arrives at the solar system and begins searching the planets for clues when it is attacked by Romulans. It destroys a Romulan ship and forces its wingmen to disengage. Enterprise then finds a crippled Federation starship, the U.S.S. Coto, in a nearby nebula. After repairing the ship, the two vessels set out for a dead moon, where the Coto's captain last heard radio traffic. They arrive, and find a Vulcan ship under attack from a small fleet of Romulan warships. After the 3 ships fend them off, the Vulcan reveals that she is Commander T'Uerell, a researcher, commanding the vessel Seleya. She insists that Archer and the Enterprise follow her back to her research station, which she suspects is under attack from more Romulans.

Episode II: Breakwater

Two other Starfleet vessels join the Enterprise and Coto as they head to the research station, Gravenor. As anticipated, they find the station under attack from Romulans. After fending them off, T'Uerell docks with the station to evacuate her people while the Enterprise and the rest of the fleet hold off the incoming Romulans. After numerous waves of attack, Archer asks T'Uerell what is taking so long, but she doesn't answer. He asks again when an Armada of Romulan Warships bears down on them, but again she doesn't respond. Miraculously, they survive the onslaught, but Archer notices T'Uerell's ship leaving and hails her again. Suddenly, Gravenor explodes, with the full crew complement still on board. As T'Uerell departs, she tells Archer that she thanks him for defending her while she recovered protomatter from the station, but that she will not have mercy on him should they meet again. Archer gives chase, but his damaged ship quickly falls behind. Frustrated, he heads back to Earth.

Episode III: Be my Shepherd

A little bit later, the Enterprise and its fleet are ordered to escort three medical ships through a system where a viral epidemic had broken out. Several times the Romulans attack, but they are repulsed. The medical ships are able to deliver the antidote, and the epidemic is cured. They confirm, however, that this virus was synthesized and was deliberately put on the planets.

Episode IV: Poisoned Well

The Enterprise and its fleet then set out to find where the virus came from. After identifying the design of a vessel seen navigating the system prior to the outbreak of the virus, the Enterprise proceeds to a planet in a nearby system. Upon arrival they are shocked to find that the virus was unleashed upon that planet as well, and that all life has been wiped out. They continue searching the system and find ships harvesting the virus from gas giants. Suddenly, Romulan ships decloak and attack. The fleet destroys them, and then discovers several harvesting stations orbiting nearby planets. They succeed in destroying them, but one harvesting ship gets away with the toxin on board.

Episode V: Stirring the Hive

The Enterprise and its fleet are heading to a nearby starbase for another assignment when they are informed by Starfleet that there is a large-scale attack being mounted near Earth by an armada of Romulan warships. They divert course, and arrive just in time to stop the Romulans from destroying a starbase. They learn that the ship with the toxin had its contents distributed to three ships, and that the trio are being escorted by the Romulan fleet. After holding off another wave of ships, the base commander hatches a plan to stop them. He proposes using the nearby mining facilities, which still use nuclear fission, to overload and disable the Romulan ships. The Enterprise and its fleet successfully distract and lure the Romulan ships. As the ships with the toxin approach, the fleet engages them from behind and disables their engines. The starbase then easily destroys the motionless ships using its cutting beam. The remaining Romulan ships disengage, and the battle ends.

The Original Series Era
Episode VI: The Squeeze

The player then assumes the role of Captain James T. Kirk in command of the Constitution-class USS Enterprise (NCC-1701) from the Original Series. In the height of a war with the Klingon Empire, Starfleet Intelligence has uncovered the development of an advanced Klingon weapons platform deep in Klingon space. Kirk is tasked with stealing a Klingon Bird-of-Prey which has been fitted with a prototype cloaking device before its systems can be brought online. While enroute to the shipyards to steal the vessel, the Enterprise assaults and commandeers several Klingon outposts to provide additional defensive capacity during the retreat. Ultimately the Enterprise succeeds in its mission to steal the Klingon vessel and its advanced technology.

Episode VII: Behind Enemy Lines

After successfully retrieving the Klingon Bird-of-Prey, Kirk pilots the vessel to the Kathra system, location of the Klingons' weapon platorm. While under cloak, Kirk in the Bird-of-Prey scan several priority strategic targets in the system, including several shipyards, the weapons platform, and a mining facility. It is at this mining facility that Kirk witnesses the presence of the Seleya, T'Uerell, and listens in on a conversation that reveals that she designed the technology behind the Klingons' weapon in exchange for mineral deposits. With this information, Kirk recommends that Starfleet conduct an immediate strike on the weapon.

Episode VIII: Firestorm

Kirk arrives with his task force in time to witness the last several Starfleet ships in the system undergo their destruction at the hands of the Klingons. After eliminating several Klingon vessels near the mining facility, Kirk and his task force proceed to destroy the Klingon shipyards, crippling the Klingons' ability to repair their vessels. Finally Kirk proceeds to destroy the Klingon superweapon, where he yet again enounters T'Uerell, who warps out of the system almost immediately after being sighted. The Klingons' weapon is destroyed, and T'Uerell vanishes with no traces.

Episode IX: At The Gates

Twenty years after the events of the previous mission, T'Uerell comes out of hiding by appearing at a classified Federation research station. Now in command of the Constitution-class Refit Enterprise NCC-1701-A, Admiral Kirk avoids going into retirement to deal with the matter, however Starfleet refuses to inform Kirk as to the nature of the research station's work. T'Uerell's control of the station includes its massive defense network, so Kirk disables it by initiating a chain reaction from the destruction of a mysterious energy source near a Klingon shipyard. Kirk regains control of the station by transporting an away team to it after a skirmish with the Klingon vessels. However, the away team reports the presence of mysterious cybernetic implants in what used to be the Klingons aboard the station...

Episode X: Omega

After arriving at the Keteract research station, a small task force moving in ahead of Kirk is suddenly destroyed by a defense grid which draws power from three energy damping devices nearby. Kirk devises a plan to disable the grid by overloading the dampeners then confronts T'Uerell, who again flees after a short conversation. She leaves behind a large Borg sphere with three mysterious orbs orbiting, which exhibits immense power. By destroying the three smaller spheres augmenting the larger sphere's subsystems, Kirk is able to destroy the sphere. However, upon the sphere's destruction, a massive explosion occurs which destroys subspace for a three light-year radius. Starfleet begins to develop an "Omega Directive" concerning the events surrounding the incident. As he contemplates his failure to capture T'Uerell, Kirk states, "Hopefully the next generation will be better."

The Next Generation Era
Mission XI: Revelations

Advancing to the 24th century, The Constellation-Class vessel USS Stargazer monitors several Romulan vessels engaged in combat with T'Uerell in a nearby star system. The Romulans are destroyed when T'Uerell uses a superweapon on a planet in the system, instantly liquefying it to molten rock and destabilizing its core. The shockwave from the weapon impact damages the Stargazer, fatally wounding captain Ruhalter and advancing the young Jean-Luc Picard to acting captain. Picard and several other Starfleet vessels successfully destroy a large quantity of stellar debris emanating from the liquefied planetary body to prevent collisions with several inhabited planets in the system, until several phaser turrets are placed nearby the planets to provide more permanent protection from the debris.

Mission XII: Ambush

Advancing further into the Next Generation timeline, Lieutenant Commander Benjamin Sisko, having recently been assigned command of the new Defiant Class USS Defiant, takes his ship to the Itari system proving grounds. There he discovers a mysterious phenomenon which prevents warp, along with several Romulan Warbirds, of which one has been destroyed. Sisko learns of the Romulans' intent to apprehend a dangerous fugitive - apparently responsible for the deaths of many Romulans. Sisko then confronts the Romulans over their illegal presence in Federation space and is taken prisoner. Captain Jean-Luc Picard, now in command of the Galaxy-Class USS Enterprise NCC-1701-D, is sent with a small task force to the system to locate and recover the Defiant and her crew. After learning of the presence of warp inhibitors in the system, the Enterprise destroys a number of warp field inhibitors and restores warp capability. Picard's team then assaults a Romulan starbase in the area and recovers the Defiant and her crew.

Mission XIII: Anger and Mercy

We advance yet again to events following the return of USS Voyager from the Delta Quadrant and collapse of the Romulan Empire in Star Trek: Nemesis. Captain Picard and the Sovereign Class USS Enterprise NCC-1701-E, along with Admiral Janeway aboard the USS Voyager, are engaged in discussions with T'Uerell - escorted by several powerful Borg vessels. T'Uerell reveals that she has assumed the role of the Borg Queen, having reformed the Collective to a tool of total logic in pursuit of her goals to eliminate all that is illogical in the quadrant. Having refused T'Uerell's demands for surrender, Picard and his task force rush to evacuate transports carrying civilian refugees from the planets in the system, which are now undergoing assimilation from the Borg. While simultaneously protecting transport ships and delaying the Borg assimilation, the refugee ships successfully escape the system.

Mission XIV: Generals

Several collaborating Romulan and Klingon fleets have successfully drawn out T'Uerell's task force and lured it to the more defendable Deep Space Nine space station above Bajor Prime. Picard and his fleet arrives just in time to rescue several of these fleets which are still engaged in combat in the system. The combined Federation, Klingon and Romulan fleets, assisted by Deep Space Nine, then confront T'Uerell and her Borg forces. T'Uerell encounters a barrage of fire unleashed by the fleets, but flees the system moments before her vessel can be destroyed.

Mission XV: Logical Conclusions

Having fled to another system, T'Uerell harnesses polaric ion energy in one of the nebulas in that system to provide a massive boost to her shields. She then opens a transwarp conduit from the Delta Quadrant using this energy to bring in Borg reinforcements. With multiple reinforcements engaging the Borg vessels, Picard devises a plan to disrupt T'Uerell and the conduit by towing two sensor platforms modified to emit a magneton pulse to positions above and below T'Uerell's vessel. This pulse destabilizes the polaric ion energy string, disabling T'Uerell's ability to harness its energy for her shields and the conduit. With the transwarp conduit closed and her shields weakened to normal strength, T'Uerell is finally defeated by the combined fleets of the Federation, Klingons and Romulans.