Mars: The Home Front is a short story written by George Alec Effinger. It is one of three examples in which the Martian invaders from H.G. Wells story The War of the Worlds are crossed over with the Barsoom stories by Edgar Rice Burroughs. The other two are The Alternate Martians and The League of Extraordinary Gentlemen. The story was first published in the anthology novel War of the Worlds: Global Dispatches.
The story is narrated first-person, in the style of Burroughs' writing, by an unnamed man who has just returned to his Virginia cabin after fishing, when, hearing a noise, he turns around and is confronted by a massive beast. He soon realizes that it is Woola, the Barsoomian calot of his uncle - John Carter, Warlord of Mars - who has appeared with the creature to relate his latest adventure to his nephew.
The narration then switches to Carter's voice as he tells his story. Carter is at a party in Lesser Helium, speaking with Kantos Kan and Mors Kajak when he realizes that Dejah Thoris has gone missing. With Kantos Kan at his side, he looks for her and finds evidence that she has been kidnapped in a scuffle; on the roof of the palace are several dead bodies of militiamen and brigands, and an abandoned flier. Assuming that the kidnappers arrived in two fliers but only escaped in one due to their losses, Kantos Kan and John Carter enter it and, finding the coordinates already set in the destination compass, activate the controls.
For half a day they fly over an unrecognized portion of Barsoom, finally coming to rest above a complex that is built around what appears to be a massive pit in the ground. They land and exited, but are beset by a band of Red Martians who use a paralyzing weapon on them and place them in a cell where an old man, a Gathol army officer named Bas-Ok, is already being held. Bas-ok explains to them that they are being held captive by the sarmaks, a leathery-skinned, tentacled race who have taken them captive in order to drink their blood due to their having no digestive organs of their own. Bas-Ok also tells them that Dejah Thoris' abductors deliberately left their flier behind with a preprogammed destination compass. They always do this when they abduct people for the Sarmaks in order to lure more unsuspecting victims to this pit.
The cell then shakes with the force and sound of a massive explosion. Bas-ok describes how that is the third explosion that happens once a day, and that it means the sarmaks have fired the giant cannon in the center of the complex again, using it to launch cylinder-ships of conquest against the inner world of Jasoom. Carter realizes that he now not only must rescue Dejah Thoris, but also help prevent the sarmaks from conquering his own homeworld. Overpowering the guards, he and his companions escape, with him sending Kantos Kan to rally the forces of Helium and with he and Bas-ok searching out Dejah Thoris.
The narration again switches back to Carter's nephew, who explains that he must wait to tell the rest of the story but gives a brief overview of what happened. Bas-ok betrayed Carter to the sarmaks and was killed for it; John Carter, after a battle in the feeding chamber, rescued Dejah Thoris and destroyed the cylinder-launching device after the tenth blast (explaining why only ten cylinders landed on Earth in The War of the Worlds), and finally how Carter led "the navy of Helium...the combined forces of the green men of Thark and Warhoon, the black First Born, and red men from many cities and nations" in a climactic battle against the sarmaks. He ends by retelling Carter's last words before returning to Barsoom: the threat of the sarmaks is over and there is no need for thoughts of revenge, as both worlds are now once more at peace.
The story is clearly set after The Warlord of Mars since John Carter is already warlord of Barsoom, but otherwise the story is a little hard to place in the chronology of the original Barsoom novels. In the story John Carter's only child is stated as being Carthoris, which would suggest the story is set before the events of The Chessmen of Mars. However; at the start of the story it is revealed John Carter has already figured out how he can take objects and even other people/animals with him when crossing the void between Earth and Barsoom; an ability he learned from Kar Komak and first demonstrated in Chessmen of Mars. Furthermore, when Bas-Ok describes the Sarmaks to John Carter, he also mentiones the Kaldanes from Bantoom, which make their debute in Chessmen. This would place the story after Chessmen.