The journal is a scrapbook comprised of the ramblings and scribbles of Frisk during her time in a mental institution. After her death, these notes and stories were put into a box along with the rest of Frisk's case files. The box containing them was tossed into the attic until Aliza found them years later. She labored to put the scribbles and notes together, to piece together her mother's troubled mind in an effort to know her.
The journal is Aliza's most prized possession, and she would not easily part with it.
The journal contains short, mad scribbles describing places and monsters in the Underground, along with outdated maps of several sections of the caverns. On almost every page, the name "Sans" has been scribbled in repetitive, begging agony.