The young student Arkenholz has an extraordinary ability: he can see dead people who appear until their death is atoned for. Following the events of a traumatic night for him, he meets the spirit of a deceased milk girl in front of a former stately home. Director Hummel, who once drove Arkenholz's father into financial ruin, observes the student's apparent soliloquy and pretends to be an old man in need of help. He swindles Arkenholz that he is not to blame for his father's misfortune and offers him a job and the prospect of his inheritance. He also presents him with the enigmatic people who live in this house: the colonel and his wife, "the mummy", who has been living in a closet for twenty years and thinks she is a parrot; her daughter, "the Miss", who lives sick in a room full of hyacinths; the spirit of the dead consul and his daughter, the dark lady and finally Hummel's former fiancee, the now aged Miss Holsteinkrona. Johannsson, Hummel's servant, tries to warn Arkenholz of his master's dark machinations - to no avail. For the traditional "ghost soup", for which everyone in the house has been coming regularly for twenty years, Hummel appears, who, as a self-appointed judge, is planning a large settlement, uninvited with ark wood. Relentlessly, he uncovers all the secrets of those involved until the judge suddenly sits on the dock himself ...

The Ghost Sonata relates the adventures of a young student, who idealizes the lives of the inhabitants of a stylish apartment building in Stockholm. He makes the acquaintance of the mysterious Jacob Hummel, who helps him to find his way into the apartment, only to find that it is a nest of betrayal and sickness. The world, the student learns, is hell and human beings must suffer to achieve salvation. The play centers on a family of strangers who meet for the sake of meeting. They exchange no dialogue, nor gestures, they simply sit and bask in their own misfortune.

To Strindberg, family was something that he could never understand or even be a functioning part of: "Family... the home of all social evil, a charitable institution for comfortable women, an anchorage for house-fathers, and a hell for children" (Strindberg's Inferno). As a child, Strindberg went through the very hell he alludes to about the family. As an adult he realized that he would rather have died than lived a childhood hell and an adult hell, thus spawning a mania fixating on death.