Linda, Bette, Gemma, and Augusta are four lifelong friends who live in Montreal. This year they're all going to turn fifty, so they decide to take a trip to New York together (courtesy of Linda's philandering husband's Visa Platinum). But at the LaGuardia airport washroom, Bette accidentally switches bags with a young mother who's actually smuggling diamonds for the mob, and things start going terribly wrong. When they kill an aggressive cab driver with pepper spray, the four friends know this is not going to be the trip of shopping and Broadway shows they'd expected.

A series of miscommunications and mishaps entangles the friends even further into the criminal underworld of New York. But out of all the bad luck (Linda's husband is staying at the same hotel as the friends, with his new girlfriend) and bad people (mobsters, drug addicts, and Linda's husband) emerge four fifty-year-old avengers of truth and justice. In the style of Crewe's Shoot Me, Hit and Mrs. is a wildly entertaining comedic romp.