Torn between faith and science, and suffering hallucinations, English naturalist Charles Darwin struggles to complete 'On the Origin of Species' and maintain his relationship with his wife.

Thomas Huxley: Mr Darwin, sir? Either you are being disingenuous or you do not fully understand your own theory. Evidently, what is true of the barnacle is true of all creatures, even humans. The Almighty can no longer claim to have authored every species in under a week. You've killed God, sir! You've killed God!
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Charles Darwin: Suppose the whole world stopped believing that God had any sort of plan for us?
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Emma Darwin: Do you not care that you and I may be separated for all eternity?
Reverend John Innes: Charles. Charles my old friend, there you are. May I join you?
Charles Darwin: Yes. Yes, of course.
Reverend John Innes: Mrs. Darwin has told me about the book you're writing.
Charles Darwin: Oh, no, no, not anymore, thank goodness.
Reverend John Innes: You mean you finished it?
Charles Darwin: It's been finished for me, actually. A Mr. Alfred Russel Wallace has arrived independently at exactly the same opinion. Expressed in a... In a mere twenty pages. Now there's brevity for you. I had covered two hundred fifty so far and have come to a dead end, so whilst having wasted twenty years on the project, I have at least rid of it.
Reverend John Innes: Well... Well, The Lord moves in mysterious ways.
Charles Darwin: Hmmm, yes he does doesn't he? You know, I was remarking only the other day, how he has endowed us in all of his blessed generosity with not one but nine-hundred species of intestinal worm, each with its own unique method of infiltrated the mucosa and burrowing through to the bloodstream. And on the love that he shows for butterflies by inventing a wasp that lays its eggs inside the living flesh of caterpillars.
Reverend John Innes: I have said on many previous occasions, it is not for us to speculate at His reasons.
Charles Darwin: Oh no, we can leave that to Mr. Wallace! Shall I advise him to stay abroad, do you think? With his opinions if he shows his face around here, he may be required to kneel on rock salt! *Snarls at Reverend Innes