Deep into a two year tour of duty guarding the Segmentum Obscurus, the SS Defiant comes across a small fleet of damaged Orc ships attempting to sneak around the main space lanes, avoiding detection and limping home.
Captain Drummett has a choice to report their heading and continue his patrol, or to give chase. Ultramarine Chapter leader Allward agrees, and the Defiant starts the hunt.
They close on the orc fleet, and immediately find a ship abandoned alone in space. A boarding party of scouts will report back on any genoforms aboard, but there is only a limited time as the Defiant cannot lose the main battle group.