The past is the present is the past
Jacob survived the virus that wiped out most of humanity, but he can't leave the past where it belongs. Tormented by nightmares, the only option seems to be returning to the source of it all and facing up to what he has done. But the past is complicated and he soon realises that putting it behind him won't be as straight forward as he thought. If he can't come to terms with what he has done and what he must do, his sanity and the lives of the people he loves may be forfeit.