Sir Howard Hallam, a judge, and his sister-in-law, Lady Cicely Waynflete, a well-known explorer, are at the home of Rankin, a Presbyterian minister.

Rankin knows Sir Howard as the brother of an old friend, Miles Hallam, who moved to Brazil after marrying a local woman.

When Brassbound arrives, he warns Sir Howard that in the mountain-country justice is ruled by codes of honour, not law courts.

He tells Sir Howard that he presides over an unfair justice system that punishes the poor and weak.

Lady Cicely intercedes and argues with Brassbound that his own code of honour is at least as brutal as the legal system he condemns.

Sir Howard says he cannot interfere, but Lady Cicely persuades him to let her tell the court all that happened on the trip.

Cunninghame Graham's book, Mogreb-el-Acksa (the ancient Arab name of Morocco) (1898), "without which Captain Brassbound's Conversion would never have been written".

The story of the legal dispute over the estate was derived from information provided about a similar case given to him by a Frederick Jackson, of Hindhead.

[1] ​Captain Brassbound's Conversion​ at the Internet Broadway Database The play was first performed at the Stage Society on 16 December 1900, at the Strand Theatre.

The first London production was at the Royal Court, 20 March 1906 with Ellen Terry as Cicely Waynflete and Frederick Kerr as Brassbound.