Four Commun'st agitators have killed a comrade while on a mission to China. A 'Control Chorus' instructs them to describe how this came about, so that a verdict may be pronounced. Their reasons for the deed are re-enacted: the victim, though a true Commun'st, had committed several serious errors in Commun'st practice and therefore agreed to his own death. They are praised by the Control Chorus for their successful work.