Who chopped off insurance agent Henry Jamison's head with a Samurai sword, and why? While trying to figure this out, Seattle private detective Jake Rossiter also has to deal with his recently promoted junior partner, Miss Jenkins, who is about to take on the Hashimoto family as clients for her first official case. Rossiter, an ex-marine who finished out World War II in the Pacific just a few years ago, couldn't care less about the Hashimotos -- Japanese Americans who were interned during the war and subsequently lost their Seattle dimestore in a suspicious fire. A Jap's a Jap as far as he's concerned. He tells Miss Jenkins that if she wants to waste her time trying to help a bunch of lousy Nips, fine, but she's on her own, she'll get absolutely no assistance from him. He's got more pressing business, especially considering that Eddie Valhalla, a notorious free-lance hit man, has just blown into town with his Hungarian bombshell of a gun-moll, ZaZu Pinske, who once used her seductive ways to doublecross Rossiter on Eddie's behalf.
Meanwhile, Captain Blevins, an old nemesis from the South Precinct, takes an inordinate interest in Henry Jamison's murder. And Jamison's widow, a big, overweight woman, becomes infatuated with Rossiter.
Then, Rossiter intercepts a death threat warning Miss Jenkins to back off the Hashimoto case, and Rossiter takes over the case to protect Miss Jenkins. But she doesn't believe he'll do enough work on it, and goes down to Chinatown to investiage, until she's ambushed and shot. Luckily, the bullet only grazes her, and Rossiter assigns one of his best operatives, Manny Velcker, to keep her out of trouble. Despite this, Miss Jenkins keeps dogging the case.
Bodies start piling up all over the place, including the shooter who tried to rub out Miss Jenkins, and a stripper named Bubbles LaFlamme, who, our detectives learn, was cozy with Henry Jamison. It seems that the bald, milquetoast Henry was quite the ladies' man. Rossiter discovers a cache of snapshots showing the mousy little Joe with bevies of scantily clad bimbos that would make even Errol Flynn green with envy. As the clues and danger mount, Rossiter and Miss Jenkins take more twists and turns than a rollercoaster, while struggling to help the Hashimotos. Jake still doesn't like Japs, but he develops a grudging respect for Frank Hashimoto, a bitter, decorated veteran who served with the famed 442d Regimental Combat Division in Europe.
In the end, Miss Jenkins forces a climactic confrontation at a gambling den in Seattle's Chinatown, which includes gun-play, flashing stilettos; a battle royale between the tall, tough ZaZu Pinske, and the pert, diminutive Miss Jenkins; and a tense showdown between Eddie Valhalla, Rossiter, and his old enemy, Captain Blevens. When the dust settles, the unexpected solutions to the tangled web of cases shock even a seasoned private dick like Rossiter.