It contains numerous diversions and non-sequiturs, such as people riding to hounds on camels, and a game of three-handed whist played by two participants, without cards, in the dark, but the core consists of the efforts of the son of the house, Kirby, to teach a collection of talking weight machines, which he has stolen, to sing the Hallelujah chorus from Messiah, and his father's decision to build a replica of the Old Bailey in the sitting room.

Elsewhere in the household Mrs Groomkirby is so obsessed with cooking that she employs a neighbour to come in twice a week to help eat the food, and the daughter, Sylvia is dissatisfied with the length of her arms.

In Mr Groomkirby's home-made Old Bailey a judge and counsel appear; Kirby is put on trial for mass murder (he kills people so as to indulge his passion for wearing black mourning) and his father is discredited as a witness under cross-examination, for failing to prove that he isn't in Chester-le-Street.

[3] Tynan took a contrasting view: "On the strength of his new play, One Way Pendulum, I suspect Mr Simpson to be the possessor of the subtlest mind ever devoted by an Englishman to the writing of farce".

[1] The critic Michael Coveney commented in 2011 that the author "mixed a comic brew that derived more recognisably from the worlds of Lewis Carroll, W. S. Gilbert and the Goons.