Barber-surgeon Johan Gustav Daadh returns to Stockholm from the war in Finland. He's taking a patient, Simon Freund, to chief constable Wahlstedt's home, where Freund has been working as a tutor. But there Daadh's life takes an unexpected turn. For one thing, he falls head over heels in love... with the chief constable's wife Magdalena. And he also becomes involved in solving a murder case, which he does so successfully that, to his surprise, he is offered the position of district commissioner, i.e. police inspector. Daadh's first reaction is to turn it down, since he's a political radical and objects to the injustices in society. But when he realises that Magdalena believes in him, he decides to accept the job, with Simon Freund as his assistant. Johan Gustav Daadh's intention is to use his new position of power to try and make a difference... in the name of justice.

Libellous pamphlets against the king are being distributed around town. When Daadh is going to interrogate the person who printed them, the man is found murdered, his skull crushed in his own printing press. Daadh's investigation brings him in contact with a beautiful and radical young French woman, and, after a few more gruesome murders are committed, Daadh realises that the old adage holds true hell hath no greater fury than a woman scorned. This is just as true of Marta Raxelius, who is convinced that Daadh killed her brother and will stop at nothing to get her revenge.