The Girl in the Cellar

A young woman regains consciousness and finds herself on some cellar steps. At the bottom of the steps is the corpse of a dead girl. She cannot remember who she is, what has happened or why she is there. Terrified and confused she manages to find a way out and, as she flees, she runs into Miss Silver, who offers to help her.
A letter in her bag is the only clue to her identity. But by investigating what has happened to her will she find herself in danger? Can she trust the letter-writer? And who is the girl in the cellar?