"You might want to tuck your trousers into your socks now," said Rennie Sparks. "This song tends to attract spiders. I think it's something to do with the timbre of my voice."

Once upon a time this sweetly smiling woman came into the life of country singer Brett Sparks and told him his lyrics needed an injection of excitement. Over eight albums and 20 years of marriage, the Albuquerque couple have since perfected the union between Brett's warm, paternal croon and limping acoustic gait and Rennie's darkly comic tales to become the masters of visionary country noir.

On Tuesday, set to keening arrangements of banjo, guitars and musical saw, there were songs about how Santa got his red suit, a sad milkman who fell in love with the moon, fire-jumping wolves and, time and time again, murder.

This was interspersed with talk about how many steak, chicken and butternut squash pies Brett had consumed that day (three), the difficulty of growing tomato plants on your roof and why Top Cat should inherit the Earth. Rennie, Brett revealed, had a childhood crush on the cartoon feline: "What could be sexier than a cat with a hat?" she confirmed. "His vest only enhanced his nakedness".

A woman whose weekly trip to Walmart is made bearable by the pack of stray dogs who've worked out how to operate the automatic doors, Rennie has the kind of over-active imagination that rarely survives into adulthood.

Between songs Brett, mopping his brow and making dry asides, was a picture of weary indulgence. Vocally, though, I've never seen him treat her wild outpourings with so much care.

There were glimmers of Johnny Cash and Elvis and, as his wife's lyrics slew another tragic bride on early favourite Arlene, his mouth slackened into a heartbreaking howl.