Harry Dresden must defeat Nicodemus Archleone, the leader of a group allied with fallen angels, to save the people Nicodemus has kidnapped--a young girl known as the Archive, and a mob boss named Gentleman Johnny Marcone. Harry Dresden is the only publicly known wizard detective in the Chicago area, and when agents of the Summer Court attack him and the Carpenter family unprovoked, he starts looking for whoever's behind it. Shortly afterward, Sergeant Karrin Murphy hires Dresden to figure out the source of an enormous pentagram configured to melt through an apparently disused building.
Dresden soon learns that Summer Queen, Titania, is trying to stop him from solving this case, though he isn't certain why; it's possible that the only reason she's opposed to it is because her Winter counterpart, Queen Mab, would consider it a favor for Dresden to do so. Mab meets with Dresden and shows him a recording of the pentagram in action. This shows Dresden that the building was a hideout for Johnny Marcone, a mob boss who was apparently kidnapped by a dozen-odd Denarians, people who've allied themselves with fallen angels. Worse, the Denarians are working with Nicodemus Archleone, who is perhaps the most frightening Denarian of all because he always plans for the long game rather than on petty short-term goals. This might well mean that Marcone is being offered a Blackened Denarius himself--and if he accepts it, Chicago will have to contend with a lord of the criminal underworld who suddenly has magic powers and is nearly impossible to keep in prison. Dresden now knows that the clock is ticking, and not just because Marcone's life could be in danger.
Fortunately, Marcone's hirelings are still around, and Dresden is able to visit Ms. Demeter, Marcone's secretary of sorts, to find out where Gard and Hendricks, two of Marcone's toughest bodyguards, are hiding. They tell Dresden more about the kidnapping, and Dresden sets up a meeting place on neutral ground with a mediator--Ivy, the Archive, a known neutral party who is extremely knowledgeable and talented with magic--in hopes of arranging Marcone's safe return.
Unfortunately, this is what the Denarians wanted, and they kidnap Ivy at the "neutral meeting", breaking the rules of the Unseelie Accords.
Dresden, working with Gard, Hendricks, and several other allies including Warden Luccio of the White Council of Wizards, and the two remaining Knights of the Cross, sets up a meeting with the Denarians. He knows that Nicodemus is likely planning to entice Ivy into joining the Denarians, which would put much of the store of accumulated human knowledge in the hands of fallen angels and human murderers, so Dresden offers something Nicodemus can't ignore: one of the three Swords of the Cross, a holy weapon whose purpose is to free the Denarians from their fallen angels' influence. Destroying the Sword would give the Denarians a distinct advantage over the Knights of the Cross in the long-term, and Nicodemus's allies bring Dresden to their base in order to facilitate an exchange.
Their base turns out to be an encampment on the island that later becomes known as Demonreach. It's practically crawling with hired thugs, but Dresden and his allies also take note of where Ivy and Marcone have been imprisoned. The exchange goes poorly, in large part because Nicodemus has a tendency to betray people at his earliest convenience, but Dresden and his allies successfully free Marcone and Ivy before Gard and Luccio arrive in a helicopter to rescue them.
Marcone, Ivy, and Sanya make it out safely, but the third Knight of the Cross, Michael Carpenter, is badly shot during the extraction, and then the helicopter is struck, forcing it to flee back to the mainland. Dresden deals with an agent of Summer who tracked him to the island, and then attempts to flee from the island via boat, but he is ambushed by Nicodemus. Dresden is able to take the Denarian by surprise by feigning that he has been disabled by a fallen angel's shadow, and Dresden eventually ends up off the boat and stranded--stuck, but alive. He is picked up and taken the rest of the way to shore by his brother Thomas and by Karrin Murphy, who show up in Thomas's boat.
Michael Carpenter pulls through.
Best part of story, including ending:
I like Harry Dresden's sense of humor, the magic system, the action sequences and many of the characters.
Best scene in story:
Dresden's final encounter with the agents of Summer who've been sent to kill him is with the Eldest Gruff, a magic user so powerful that Dresden knows he has no chance of surviving a stand-up fight between them. So Dresden calls in a favor from Summer--not to let him live, since that would directly contradict the Eldest Gruff's orders, but to give Dresden a freshly-made, genuine Chicago doughnut before Dresden's death. By fulfilling this request, Eldest Gruff will have to leave the island just long enough for Dresden to escape, and since their conflict will at that point be moot, this means that the Summer Queen's orders will be rescinded and Eldest Gruff won't have to kill Dresden after all.
Opinion about the main character:
Dresden is funny, quick on his feet, brave, and capable of using his powers in a variety of creative ways. In general, he's interesting to read about, and his view of the world is often amusing.