The Bat is a Broadway play by Mary Roberts Rinehart and Avery Hopwood first produced in 1920. The plot relates how wealthy spinster Cornelia Van Gorder and her guests uncover a mystery at their rented summer home while being stalked by an enigmatic, costumed criminal known as 'The Bat'. The story takes place in an old mansion, where people look for hidden loot while a caped killer (The Bat) murders them one by one.