
The last living construct
The living construct, or simply the construct, was a weapon created by the Vau N'Akat, designed to turn enemy computer systems against themselves.
History[]
Original timeline[]
In the 25th century, when the USS Protostar emerged from an unstable wormhole over Solum, the Vau N'Akat captured the ship and installed their last surviving construct aboard, planning to send it back in time to destroy the Federation and thereby avert the fateful first contact between their peoples. Captain Chakotay and Commander Adreek-Hu managed to escape captivity but were unable to disarm the weapon or board the ship to escape. As a last resort, Chakotay launched the ship unmanned back through the wormhole before the Vau N'Akat could enact their plan. (PRO: "A Moral Star, Part 2", "Preludes")
In 2384, the Diviner told his daughter Gwyn about the construct and its purpose. However, Gwyn lost her memory of the conversation after seeing a reflection of Zero without their containment suit. (PRO: "A Moral Star, Part 2")
The crew of the Protostar later visited the Federation relay station CR-721 to seek asylum. When the station's sole crew member, Lieutenant jg Barniss Frex, attempted to download the Protostar's logs, the construct activated and caused the station to destroy itself. As the Protostar crew fled the doomed station, Gwyn remembered what her father had told her. (PRO: "Asylum")
The crew subsequently located the construct in a hidden subdeck below the bridge, but could not disable it. Thus, they decided to access the vinculum of a dormant Borg cube to seek any information that could help them. The Borg Collective analyzed the weapon and indicated that it could not be removed or deactivated. They then attempted to assimilate the Protostar so they could use the construct themselves, but the Protostar was able to escape. (PRO: "Let Sleeping Borg Lie")
Meanwhile, Frex informed Vice Admiral Kathryn Janeway of the presence of an unknown weapon aboard the ship. Unfortunately, a rogue faction of the Romulan Tal Shiar were also made aware of the weapon, who attempted to steal the Protostar and its dangerous technology for themselves while it was stranded in the Romulan Neutral Zone. It was only by the narrow intervention of Dal and the Protostar crew that this was averted. (PRO: "Crossroads", "Masquerade")
With no way to deal with the construct directly, the Protostar crew had to flee from Starfleet. However, when they chose to give up on contacting the Federation altogether, a hidden Vau N'Akat subroutine in Hologram Janeway's coding allowed the living construct to intervene and forced Hologram Janeway to trap the Protostar crew in the holodeck and take the ship herself, passing the USS Dauntless into the heart of Federation space. (PRO: "Masquerade", "Ghost in the Machine")
When Zero and Dal attempted to telepathically warn Janeway of the Living Construct's exact nature, their psychic connection accidentally swapped Dal and Admiral Janeway's neural patterns. During this time, Admiral Janeway learned the full truth of the weapon and the predicament aboard the Protostar. Because Hologram Janeway was a non-essential system, Admiral Janeway was able to remove the Construct's corruption from her holographic counterpart before she returned to her own body. (PRO: "Mindwalk")

The construct transmitting its signal across the fleet
Unfortunately, the Vindicator, in her guise as Trill Ensign Asencia, was able to activate the construct when she contacted the Dauntless. The construct was able to spread its corruption to Dauntless and other Starfleet ships that arrived in response to its distress signal. Despite assistance from the Federation's allies, such as the Klingons, Ferengi and Gorn, the construct continued to corrupt Starfleet's vessels as they destroyed themselves and their allies. Realizing the situation would otherwise end with Starfleet's annihilation and seeing no other way to remove the construct, the Protostar's crew elected to destroy their ship. The ship, under the command of Hologram Janeway, was destroyed along with the construct, ending the signal as there was no longer a source. (PRO: "Supernova, Part 1", "Supernova, Part 2")
Altered timeline[]
In an altered timeline, Chakotay and Adreek-Hu escaped with the Protostar instead of sending it back alone, resulting in the ship never reaching Tars Lamora. (PRO: "Who Saves the Saviors") In this timeline, the ship landed on Ysida in 2374 after the proto-core and antimatter were ejected to ensure that it could never fly again and thus the living construct wouldn't pose a threat to the Federation. (PRO: "Last Flight of the Protostar, Part I")
After finding the Protostar on Ysida, the crew revealed to Chakotay the events with the living construct in their timeline, that the Federation was aware of it, and the living construct was no longer a threat if the Protostar were to be launched. (PRO: "Last Flight of the Protostar, Part I")
After the Protostar rendezvoused with the USS Voyager-A, Starfleet was able to render the living construct ineffective against their ships by using an anti-virus upgrade developed with Starfleet's previous experience fighting the weapon and the chance to study it while the device was inactive. (PRO: "Ascension, Part I")
The Protostar was later sent back in time to Tars Lamora with the weapon onboard in order to repair the broken timeline. (PRO: "Ouroboros, Part II")
Technical data[]
The living construct was located in a sub-deck accessible via a hidden hatch on the bridge, which was marked with a symbol of Solum not visible to the naked eye. When another Starfleet vessel contacted the Protostar, the weapon would transmit a signal that would corrupt the computer of the other vessel and turn its systems against itself, causing its destruction. The construct behaved as though it were alive and could change shape to defend itself from threats. Given the near-insurmountable difficulty in removing a construct, the only reliable recourse for any ship with one installed was to self-destruct, especially if it was already corrupting vessels. (PRO: "A Moral Star, Part 2", "Let Sleeping Borg Lie", "Supernova, Part 2")
Starfleet was later able to develop an anti-virus upgrade to render the living construct harmless to their ships after the battle it instigated and a chance to study it on the Protostar from an altered timeline. (PRO: "Ascension, Part I")