Petra is a short story included in the 2010 reissue of Halo: First Strike, written by Christopher Schlerf. Taking place after the Human-Covenant War, it details the thoughts of Petra Janecek, an experienced war journalist as she pursues a new story. The story also gives a glimpse of the era after the war.
Janecek has arrived on Forseti, a colony untouched by the Human-Covenant War, whilst collecting material for a possible new story relating to secrets surrounding the final days of the war. Staying in Forseti Northern Terminus 37 in Four Winds, she has managed to get her hands on the transmission sent by Cortana to the UNSC from High Charity after the Flood overwhelmed it, where she reveals that there is a "solution" to the Flood at the Ark without firing the remaining Halo rings. This leads Janecek to speculate on the possible different interpretations of the message, including the use of the Ark as a weapon.