Ibsen's Gengangere has always, for want of a better word, been entitled Ghosts in English. The play also has a subtitle, A Domestic Drama in Three Acts, which highlights the author's questioning of the family as an institution – as he had done in A Doll's House two years earlier.

Once infamous, now famous and frequently performed, Ghosts consists of a network of gradual revelations. Returning from Paris to his parental home in Norway and doomed to a premature death through syphilis, Mrs Alving's son Osvald learns that he has inherited his illness from his promiscuous, since long deceased father and that Mrs Alving's maid, Regine, with whom he wants to start a relationship, is actually his half-sister. The orphanage that Mrs Alving has just erected in memory of her late husband burns. Carpenter Engstrand, once paid off to play the role of Regine's father, persuades the naive Pastor Manders that it is Manders’ carelessness that has caused the fire – whereas it is obviously Engstrand himself who has done so. Engstrand promises to keep the reason for the fire secret, thereby saving Manders’ reputation. In return for this Manders promises to help Engstrand start “a seaman's home” entitled Court Chamberlain Alving's Memorial Home to replace the burned orphanage. Yet, since the seaman's home is Engstrand's euphemism for a brothel, the new “Captain Alving's Memorial Home” ironically becomes a home, not for orphans, but for those who beget them – promiscuous men and women – and in this sense a home in the image of Alving. Having discovered that Alving is her real father and that a relationship with her half-brother Osvald therefore is impossible, Regine leaves, presumably to take up a job as a prostitute in Engstrand's brothel. Left alone with his mother, Osvald hands her a mortal dose of morphine and asks her to give it to him when the illness reduces him to a helpless child – which soon occurs. Leaning over her now demented son, Mrs Alving hesitates to give him “the last service.” There the play ends.

Usually considered a prime example of naturalistic drama, Ghosts strictly adheres to the unities of time and place. Set in the same room for all the three acts, the play begins shortly before noon, we may assume, and ends at sunrise the next day.