In 09_018M42 the lure of the Foramen Ignotum and the strategic benefits its discovery and control would bring, led to the dispatch of small teams from various powers into the Hadron expanse. A large expedition would be expensive, inflexible and might illicit a response from either the necrons or another enemy. In addition, no one knew where the Ignotum was, or whether it even existed, so the hunt for the last Foramen was undertaken by forces that could slip under the radar.
Archmagos Cybixx send his own team, informing Inquisitor Vorushko that he would seek to prevent the Foramen Ignotum from being discovered or opened, and by 1009_018M42 the Archmagos had several teams actively hunting for information, based around a single Adeptus Mechanicus Explorator vessel. They soon discovered they were not the only force in the Expanse however, as the Emerald Serpent engaged one of Cybixx's teams, forcing them away from a world in one uncharted system. Indeed the Crusade Mechanicum found the exploration of the expanse tough going in 09.018M42, as an elite force of Novgorod Guard sent by Hathek on the same mission ended up following Cybixx's teams and attacking them wherever they could, proving a thorn in the side of the mechanicum. The Crusade force did however manage to find one lead in the presumed dead system of HE-199478/C, but they also discovered a small tomb full of necrons from the Bahotek dynasty, and were only just able to make good their escape, killing the necrons which had awoken and quarantining the world.
The other force intent on finding the Ignotum passageway was the Emerald Serpent. The tzeentch dedicated faction sent its own teams of Thousand sons warbands, often aided by the Wraiths of Prospero, who unfortunately encountered loyalist Adeptus Mechanicus forces, wiping one of the Emerald Serpent's investigations. Other warbands were more successful however, as the traitor marines overcame a squad of Hammers of the Emperor who had tracked them to the fourth world in system HD-X334-1.
Progress of the Imperial and chaos factions was however impacted from an unlikely source. A space hulk, already encountered in the expanse, had mysteriously disappeared, only to reappear out of the warp near the Rifts of Hecate. Wondering whether the movement of the hulk had a relationship with the Foramen Ignotum, the Emerald Serpent and their death guard allies boarded the Hulk. The chaos forces had almost no opportunity to explore however, as the genestealers attacked both teams with unprecedented fury, driving them both off and inflicting heavy casualties. The chaos forces had however established that the Hulk did indeed hold a clue to the mystery of the Ignotum, but as yet, no one had been able to retrieve it.