In this addition to the Commissaire Adamsberg series, has a serial killer followed Adamsberg to Canada on his training mission? Between 1943 and 2003, nine people have been stabbed to death with a most unusual weapon; a trident. In each case, arrests were made, suspects confessed their crime and were sentenced to life. One slightly worrying detail - all the presumed murderers lost consciousness during the night of the crime and cannot remember whether they actually did it or not. Commissaire Adamsberg is convinced all the murders are the work of one person - the terrifying Judge Fulgence. Years before, Adamsberg's own brother had been the principal suspect in a similar case and avoided prison only thanks to Adamsberg's help. History now repeats itself when Adamsberg, who is temporarily based in Quebec for a training mission, is accused of having savagely murdered his young lover. In order to prove his innocence, Adamsberg must go on the run from the Canadian police and find Judge Fulgence.