A third mission, "Zeus III", lands on Mars in June 2001. It is commanded by Col. Wilder himself with five other astronauts (Spender, Parkhill, Briggs, Cook, McClure) as subordinates. The crew discovers five ancient cities in the vicinity of the spacecraft, one of which apparently was inhabited only a few weeks ago. The scientists find that all of the Martians have died of chickenpox accidentally brought from Earth by the first two Zeus crews. The men, except for the archaeologist Spender and Colonel Wilder, become more boisterous. Spender loses his temper when Briggs starts dropping empty wine bottles into a clear blue canal. He knocks him into the canal. He leaves the rest of the landing party to explore Martian ruins. Spender (who always has had deep misgivings about the mission) then goes on a killing spree to avenge the destroyed Martian civilization and manages to shoot all astronauts except Parkhill and Wilder, who shoots Spender in the chest before he has the opportunity to kill them as well.