Ailla and Koschei had become stranded on Earth for several years when Koschei's TARDIS was irreparably damaged in a battle with a disembodied entity which tried to shroud the world in a web-like substance. When the Conclave learned of the TARDIS's abilities to travel sideways in time from video surveillance records of the Third Doctor's arrival and his subsequent activities at the Inferno Project, this led to plans to escape their dead world. However, when Koschei refused to help the Conclave evacuate to a parallel Earth, he and Ailla were imprisoned and tortured for information about how to operate his TARDIS's control console (the only part of Koschei's ruined craft that was salvageable), which would be used by the Conclave to open dimensional portals to the regular Earth timeline.