Duct Soup is the fourth episode in Series VII of Red Dwarf. It is the fortieth episode overall. After the temporary departure of Arnold Rimmer earlier in the series, and the introduction of Lister's old girlfriend Kristine Kochanski in the last episode, Duct Soup was intended as a "bottle episode" (in the style of Series III episode "Marooned") to better acquaint viewers with the new character line-up that would remain for the duration of Series VII.