Calder is a Fetch, an escort of sorts. He delivers souls who have just died to Heaven. He waits at their 'Death Door' until they choose life or death, then opens the door into the 'Aisle of Unearthing' and guides the soul through the different elements of the Aisle until he hands them over at the 'Great River'.
Calder makes a mistake and unleashes lost souls into the living world during the Russian Revolution. He must make things right and save Ana (Anastasia) and Alexis.