The Mona Lisa was a freighter repurposed for the transportation of prisoners between colonies in the later years of the Human-Covenant war. The ship and crew were unarmed as a contingency in the event of a convict breakout, thereby rendering the crew defenseless to a Flood outbreak which overran the ship and killed most of the crew in 2552, after the destruction of Installation 04.
When the Mona Lisa arrived at the wreckage of Installation 04 in the Soell System weeks after the Halo Event, its true purpose was put into action. Surveying the wreckage and finding Sangheili survivors, the ship then took them as prisoners. One of particular interest to the ONI operatives on board was one suffering from a strange infection. ONI planned to study the infection, either looking for a cure or way to control it. However the Elites and human test subjects broke quarantine and infected the ship, beginning the process of building a Proto-Gravemind to attempt FTL travel without needing access to the bridge, which was locked off.
However, when the UNSC Red Horse arrived at Installation 04, a squad of Marines among her crew was sent to investigate it, at first presuming it derelict. They split up, looking for survivors, but were quickly alerted to the horrors of the ship. Among its survivors were "Henry", an Elite who teamed with a prisoner named Patrick Rimmer, and John Smith, an ONI operative responsible for the experiments on board. The ship is then ordered to be destroyed by Rebecca, the Red Horse AI, by a Shiva-class Nuclear Missile. The squad was slowly whittled down as the action continued, until they reach the escape pods. Only four members of the squad survived (Lopez, MacCraw, Clarence, and Benti), along with Henry and Rimmer. While upon reaching the escape pods, Clarence shot Rimmer and it was revealed that he was an ONI operative sent to "clean up the mess". The remaining survivors were caught in a standoff pointing guns at one another as the Flood was approaching their position and during this pause, MacCraw took off in one of the escape pods. A wounded Benti jumped on Clarence and took them both out into the hallway where they were overtaken by the Flood. Sergeant Lopez, the leader of the squad, and "Henry" fought over the last remaining escape pod, presumably to one or both of their deaths. The ship was subsequently destroyed.
- The Mona Lisa resembles the Imperial Dungeon ships from Star Wars, and both ships have the same purpose, to carry prisoners.
- The Ship was probably named after the famous renaissance portrait The Mona Lisa, painted by Italian polymath Leonardo da Vinci in the early 16th century.
- The Mona Lisa also resembles the USG Ishimura from the Dead Space franchise. Ironically where the Mona Lisa suffers from an infection from the flood, the Ishimura suffers a similar infection from an alien artifact known as "The Marker".
- ↑ Halo: Evolutions - Essential Tales of the Halo Universe, page 223-342