The best book I read this month was a romp featuring four 60-year-old assassins. Yes, you read that right—I used the words romp and assassins in the same sentence. I never thought I’d describe a book about murder as fun, but that’s exactly what Deanna Raybourn’s Killers of a Certain Age is: fun.

Billy, Natalie, Mary Alice, and Helen are celebrating their retirement—from nearly forty years of working as assassins—when they discover they themselves are targets for assassination. What follows is part murder mystery, part buddy road comedy, part revenge drama.

It was a delight to read about women “of a certain age” without the focus being on divorce or loss or aging. Loss and aging play a role here, but these women are not going quietly into that good night. They are action heroes—smart, sassy, capable, and kick-ass. I loved it. I want more books with characters like these women—mature, strong, and badass.