When new clues from the diary of her long lost brother, help a young woman to solve a riddle of decades old crime, she is compelled to go to Siberia in search for her vanished family and a missing treasure.

This logline does not reveal any conflict, inner or outer. Is there an antagonist or something she must fight against.

Corridorone.

From the posts above it seams that each iteration of the logline is getting a number of consistent comments. I suggest implementing these notes as they mostly still apply to the latest draft of the logline.

Perhaps tighten a bit?

After a daughter uncovers her dead brother's diary, she scrambles from Brazil to Siberia searching for her family and her birthright fortune.