The lives of the inhabitants of Swevenings are disrupted only by a fierce competition to catch the Old Un, a monster trout known to dwell in a beautiful stream which winds past their homes.

Then one of their small community is found brutally murdered; beside him is the freshly killed trout. Both died by violence - but Chief Detective Inspector Roderick Alleyn's murder investigation seems to be much more interested in the fish....

Scales of Justice was first published in 1955.