Z shift was an apparently two-man, low-priority maintenance team aboard the JMC ship Red Dwarf. Third Technician David Lister (the lowest ranking member of Red Dwarf) was assigned to Z shift under the command of Second Technician Arnold Rimmer (the second lowest ranking member on the ship). This "graveyard shift" was occasionally and begrudgingly supervised by Second Officer Frank Todhunter, who had to deal with Rimmer's many complaints about Lister. The two Z Shift workers, Rimmer and Lister, were also bunked up together, as crewmen of equal rank frequently were.