The British Empire, suddenly finding itself with an interdimensional portal due to a Weird Science experiment gone awry, has discovered a new world, the Gruv, chock-full of resources and land to be exploited. In the process, though, they've run headlong into the Samsut, descendants of ancient Babylonians who've been living there for over three thousand years. Now the might of the Empire clashes with the weird science of the Samsut. The Saurids, a reptilian race native to the new world, contest with both empires to retain their ancestral lands. Who will control the Gruv? Meanwhile, first in London and then around the world, magic has returned. In some cases, humans have changed, becoming elves, dwarves, snarks, and trolls. In others, mages, priests and shamans have gained awe-inspiring powers. Weird Scientists build unexplainable devices. Technological leaps forward have given us British microsteam engines, Confederate Giffard airships, and Prussian lightning guns, with new world-changing inventions appearing every day. Dodgers skulk in the shadows, doing what reputable firms need to be able to deny. The British hold title to the Rabbit Hole and its access to the Gruv, but other nations have brought pressure to bear, and will not be denied their chance at the riches of the new world. Intrigue! Exploration! Giant insects! Battery-powered zombies! War in the New World and the threat of it in the Old! Where will all this end? That's for you to decide! The 1879 Game Master's Companion expands upon world building of the Game Master's guide, providing new challenges to give your players and new possibilities to take your story. Additional information on vehicles has been provided, including several new ones that range from simple transportation to all new tools of war. Additional Secret Societies are detailed, giving potential new friends and foes for your players to encounter, and possibly new groups they may wish to take part in. The Victorian era is not a kind one when it comes to health, and further details are provided on some of the nasty circumstances that for the time are part of every day life. If you've run out of fresh encounters to throw at your players, the book includes methods of creating new creatures, as well as an abundance of ready made new ones. If you need to bring the challenge up to the next level, new spirits and even dragons are detailed. Finally, the book provides an extensive time line of events leading up to the present time within the game. Get ready to delve even deeper into the world of 1879 with the next set of twists to navigate and obstacles to overcome!