First appearance: Galaxy Science Fiction, October 1966.
The 15-man team setting up the first base on Mars experience tragedy when a murder is committed. Carter, the murderer, in the process of escaping on one of the transportation buggies crashes through the plastic bubble which holds in the base's atmosphere in an attempt to kill everyone else; however, it fails, and he is soon chased by Alf, the brother of the victim on another buggy.
The lethal chase, with the two combatants in constant radio communication, slowly reveals the community stresses which resulted in the murder. Alf wants to kill Carter in revenge for his brother, while Carter wishes the same and to try once more to destroy the base .... but with limited oxygen in their tanks, the two men must ensure that they have enough left to return to base.
Published in the collections The Shape of Space (1969, collection), Inconstant Moon (1973, coll), Tales of Known Space: The Universe of Larry Niven (1975, collection), Three Books of Known Space (1996, coll)