Mona Lisa

The UNSC 'Mona Lisa was a prisoner ship that was in service into the late years of the Human-Covenant War. Being a prison ship, it was in reality a converted freighter, meant to transport ore and prisoners to and from penal colonies. As it was, it was mostly unarmed, as prisoners ships usually were, though mysteriously without an escort to prevent escaping convicts.

Installation 04
Arriving at Installation 04 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 The Flood. ONI planned to study the infection, either looking for a cure or way to control it. However, that Elite, and its infection, would break quarantine and infest the ship, beginning the process of building a Proto-Gravemind to attempt FTL travel without needing the bridge's proximity, which was locked off.

However, when the Red Horse arrives at Installation 04, a squad of Marines among her crew investigates it, presuming it at first derelict. They split up, looking for survivors, but are quickly alerted to the horrors of the ship. Among its survivors were "Henry" an Elite who teamed with a prisoner named 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 salvo of Shiva Missiles The squad is slowly whittled down as the action continues, until they reach the escape pods. Only two members of the squad survived, and Henry. Lopez, the leader of the squad Elite fought over the escape pod, presumably to one or the other's death. The ship was summarily destroyed.