A little rain on Thursday

When Beth inherits a old stone church in Sydney. she moves in with her boyfriend Jack. After the couple moves in, Jack stumbles on a manuscript hidden in the crypt. It's written in a strange hand in an unknown alphabet with peculiar illustrations, and something about it promises great secrets. Bit by bit Jack grows obsessed. Is this bizarre book a hoax or in some kind of code? How old is it? Is it the key Beth needs to understand her father? Or does her answer lie in the box of old family photographs she finds in the church?