The first novel in the series, Storm Front is light on the Myth Arc and doesn't include the Loads and Loads of Characters common to the later books; its pacing is also slower as the reader is introduced to one Harry Dresden, Wizard.
Our hero is living day to day as Chicago's only professional wizard (he's in the phone book, look him up). Mostly he does small jobs — exorcisms, lost objects, the occasional police consultation on the side. So when a middle-aged woman named Monica calls to ask him to find her husband, no police necessary, he's not in a position to say no. Sure, the guy's probably having an affair on the side, nothing magical about it, but a paycheck is a paycheck.
His plans are interrupted when his Friend on the Force, Lieutenant Karin Murphy of "Special Investigations", calls him in to do his thing. A couple have been murdered at a local hotel with black magic, with their hearts impossibly exploded out of their chests. Complicating matters are the identities of the deceased: she's a High-Class Call Girl working with a vampiress, he's hired muscle for the city's most notorious crime boss, "Gentleman" Johnny Marcone.
Whom he runs into immediately after leaving the crime scene, 'inviting' the wizard into his car for a ride back to the office. Marcone takes Harry off guard by offering to hire him - to not do much of anything for the next couple days. Particularly, to not help Murphy with her investigation. Harry refuses, and Marcone tricks Harry into a soul gaze, which lets a wizard plus one see who the other truly is as a person in exquisite detail, with the added caveat that not a single detail of what is experienced will ever fade from memory. Harry is shaken by the soul of the crime lord, but refuses to back down. Marcone drops him off outside his office building in time for his appointment with Monica.
Harry's client is a messed-up bundle of nerves, refusing to meet Harry's eyes. Her husband, Victor Sells, who had lost his job recently and no friends or family besides Monica and their children, has been missing for three days. He even packed a bag before he left, but Monica insists that he would never leave them. The runaway spouse looks more and more likely, until Monica reveals the reason she went to Harry and not the police: Victor had recently developed an interest in magic. Harry promises to see what he can do. Monica heads off to pick up her kids, leaving behind an advance payment, a photo of her husband, and a talisman he had been using - a dead scorpion. Not inherently evil, Harry notes, but certainly not a good sign.
Harry takes one of the fifties from his advance pay, and treats himself, heading on over to McAnally's pub, the popular hangout spot for Chicago's supernatural subculture. After ordering a steak and one of Mac's almost supernaturally good beers and gossiping about the new designer drug, Three Eye, Harry is accosted by Susan Rodriguez, a tabloid reporter who knows Harry's the real thing. She questions Harry doggedly about his case, learning a little bit due to Harry's sheer inability to lie convincingly, before asking him to dinner and leaving. Women, Harry figures. Way more mysterious than wizards.
Caught in a struggle between Marcone, the vampires, and a shadowy third figure intent on removing him from the picture, Harry has to think fast and fight faster before someone finds him guilty — or finds him dead.