"Vengeance on Mars!" by D.B. Lewis is a science fiction short story written in the early 1950s, reflecting the themes of desperation and moral conflict often found in space exploration narratives of its time. The story explores the complexities of friendship and betrayal against the backdrop of a dangerous Martian environment, as characters navigate their relationships and the harsh realities of frontier life. The plot centers around Hale, who must confront his former friend Randy, a looter who has killed a guardian in a Martian water temple. Caldwell is caught between his loyalty to Randy and the necessity of ensuring safety for the colonists threatened by Randy's desperation and violent actions. As Hale tries to reach out and persuade Randy to surrender, old memories and unresolved feelings resurface, leading to an intense confrontation where survival instincts prevail. Ultimately, Hale must come to terms with the dark transformation of his friend, highlighting the costs of betrayal and the relentless nature of life on Mars. (This is an automatically generated summary.)