Harry Dresden, professional wizard - he appears in the phone directory under "Wizards", after all - receives a call: a woman wants to hire him to find her missing husband. About the same time, Lieutenant Karrin Murphy, head of Special Investigations in the Chicago Police Department, asks for his help to solve a mysterious crime, that of a man and a woman whose hearts exploded while they were having sex. The man turns out to be connected with Johnny Marcone, the local Mob boss, who tries to get Harry to forget about the case. Then there's the new magical drug on the street, Three-Eye, which forcibly opens the True Sight. This is not a good thing, given how horrifying some things are in the Sight.
Harry tries to take on both investigations at once, which proves easier than expected because of their interconnections. He investigates people connected to the dead woman (a prostitute), including a coworker and her Red Court vampire boss, Bianca. The meeting with Bianca doesn't go very well- when Dresden bleeds, Bianca loses control and attacks him. He defends himself, and her frazzled mental state later causes her to overfeed from and kill one of her human thralls. Remember this, it'll be important later.
With the Bianca angle a bust (though he got some help from the coworker), he starts investigating the missing husband, Victor Sells, and (with some help from his dewdrop fairy informant Toot-Toot) discovers that he may have been engaged in sex rituals. Also, he seems to be a magic user himself, new and untrained but fairly strong. He's using his powers to create Three-Eye, as well as to make the hearts of his rivals explode out of their chests.
Harry has a confrontation with Morgan, a Warden of the White Council and Harry's parole officer. Morgan is quite prejudiced about Harry (believing that Harry is a warlock) and just waiting for him to screw up, but summoning Toot-Toot does not really constitute a break with the Laws of Magic, so he has to let Harry go.
And apparently Victor Sells is strong enough to send monster scorpions and a demon after Harry and explode even more hearts. Harry's his next target, but he can't hit him with the heart-exploding spell quite yet. Turns out, he was using storms (as well as sex energy from two of Marcone's old enemies) to power the spell. If Harry can't get to him before the next storm, he's toast.
Harry manages to find Sells and interrupts his spell at the last second. They have a showdown in the house, which ends with Sells unwisely shouting out his demon's True Name to summon it right in front of Harry. You see, anyone who knows a demon's Name can control it, and Harry uses the demon's Name to free it from Sells' control. The demon kills Sells.
Harry is saved by Morgan, because as triggerhappy as Morgan is, he is also honorable, and realizes that what Harry did was not the actions of the warlock. He also argues for the Council to lift Harry's parole, which happens.
- Battle Amongst the Flames: This happens for the first (but definitely not last) time in Victor's house.
- Chekhov's Gun: A lot. Some that take several books to be fired, even.
- Combat Pragmatist: Both Harry and Victor use guns in combat. Harry also gets props for re-designing a cleaning spell to use against the scorpions. He also got all the dust, too.
- Foreshadowing: The Three-Eye addict provides an awful lot of foreshadowing for someone who appears in one scene. He mentions important things from Fool Moon and Cold Days, as well as an important event in Harry's backstory.
- For Want Of A Nail: About two thirds - perhaps even more - of Harry's problems in future books can be traced back to one instant.Bianca: You're bleeding, Mr. Dresden.
- I Know Your True Name: It's established that knowing a supernatural being's true name can give you power over them. It's unwise to do this to the more powerful beings, though, since it gives them a chance to hit you back, and it's also far less effective against mortals, who constantly change and reevaluate their natures, which changes their true name.
- Our Vampires Are Different: This book introduces the Red Court, batlike monsters in a human 'flesh mask' who feed on blood and have addictive saliva.
- Strong, but Unskilled: Victor Sells, who is about as powerful as Harry at this point, but has no combat skill.
- Red Baron: Nobody can make the title 'Gentleman' sound quite as badass as John Marcone.
