Begotten is considered by Merhige himself as the start of an unofficial trilogy. There is a prologue to the intended second installment in the trilogy, which is the 14-minute short Din of Celestial Birds, which deals with evolution and premiered in 2006 on Turner Classic Movies, and was shot in similar visual fashion as Begotten.
A love story about two beings that believe themselves to be ONE. Two alien creatures: completely distressed and confounded by their separation. The film is a ritual enacted, where each find the other across time and space as they try to become the other literally and physically, in the process creating a new utopia, a mythic city where the two beautifully merge to become a new kind of creature, a new form of god.