Nil Admirari no Tenbin: Teito Genwaku Kitan

The story is set in the Taisho Era at the beginning of the 20th century—except the era did not end in 15 years (as it did in real life) but lasted 25 years. To protect her family who fell from their former glory, a girl decides to marry a man whose name she does not even know. However, before she does, her little brother commits suicide in a mysterious fire, with an old book in hand.