A Machine for Pigs takes place 60 years following the events seen in The Dark Descent, specifically, New Years Day 1899, London.
“A rich industrial tycoon named Oswald Mandus collapses from a feverish nightmare in which he sees a mysterious, dark machine. A “disastrous” and tragic expedition to Mexico, compounded with his illness, have stolen months from his life and he wakes determined to piece together the missing fragments of his life.”
Sounds deceptively simple, to me.
As far as explaining what exactly the title has to do with anything, Pinchford told Joystiq, “This world is a machine fit only for pigs. Fit for the slaughtering of pigs.”
Amnesia: A Machine for Pigs has no set release date, but I’d imagine that the two teams are scrambling to get the game out by Halloween 2012.