The Engineer tasks Mandus with clearing the floodwaters and bringing the Machine back online, providing ongoing guidance through telephones throughout the facility. The Machine has been sabotaged, putting his sons in danger. Mandus receives a call from 'the Engineer', who tells Mandus that Edwin and Enoch have been trapped far below them, in the 'Machine' which Mandus created beneath his house. He hears the voices of his sons, Edwin and Enoch, calling for him as they lead him through the different areas.
At the beginning of the game, he awakens from a fever that has lasted for several months, after returning from a disastrous expedition to explore Aztec ruins in Mexico. Set in London on New Year's Eve, 1899, the game's protagonist is Oswald Mandus, a wealthy industrialist and butcher who is implied to be the great grand-nephew of Daniel, the protagonist of Amnesia: The Dark Descent.
Some take place in the past, some in the present, and some are overtly real while some may be imagined. The game features several interlocking storylines.
