The story centers on two young women, 19-year old Irene “Rally” Vincent and her partner, 17-year old “Minnie” May Hopkins.

Rally and May operate the titular “Gunsmith Cats” gunshop in Chicago, Illinois. Rally also works as a bounty hunter, assisted by May, which is the impetus behind many of the stories. Rally characterizes bounty hunting as her “hobby” though it is in fact her main source of income.

Rally is an expert combat shooter and markswoman with just about every firearm in existence, as well as an expert driver. May is an explosives expert, knowing the inner workings of and many uses of all manner of explosive devices.