Picture a desert stretching endlessly out across the horizon until being disrupted dramatically by the rise of the Andes. Barren but beautiful, like a scene out of Walter Salles’s Motorcycle Diaries.

Now cut to over ten million people captivated by two musicians delivering the most intimate of performances at an arts centre in a remote city nearby. A young woman in a red dress, face contorted with emotion, weaves the notes of her double bass around a breath-gentle voice, accompanied by barely-there jazz chords on an electric piano. The setting is San Juan Argentina, the year is 2017 and they were performing Barro Tal Vez, an achingly intense but minimalist Argentinian song and it went viral on YouTube. So begins the almost unbelievable story of Cande Buasso and Paulo Carrizo.

The song was written by the Argentine poet and rock legend Luis Alberto Spinetta at the age of fourteen – it’s about the transmutation of the soul. This was the first time that Carrizo and Buasso had appeared together, partnered up by the municipal theatre of their hometown. The song was, in essence, their first date, revealing a musical chemistry so rare, the pair knew they had to act fast.

Fast forward two years, thousands of air miles and a global record deal later and this most captivating of musical couples that we’ve seen in years present their debut single, recorded with the famed producer Larry Klein (Joni Mitchell, Bob Dylan, Herbie Hancock) in LA. Carrizo’s intensely musical arrangements, the pair’s deep sensitivity for transmitting the emotional heart of a song, and Buasso’s voice, mature beyond its years, but innocent enough to suggest the sense of someone singing to the world for the first time make for a truly exquisite debut.

Like many of the great love affairs, the scenes of this unusual partnership were sewn long before the couple went to work on the Spinetta tribute. San Juan – a city of 120,000 nestled in the Tulúm valley with a stunning desert landscape – has no major record labels but is home to a thriving independent music scene: a giant family, Buasso calls it, preserving a kind of “village life”. Incredibly, the pair first met when she was fifteen, a restlessly creative child who had told her mother at four that she fully intended to be famous. Carrizo, a multi-instrumentalist and arranger equally at home in classical and rock music (his latest album with The Paulo Carrizo Trio combines flamenco and jazz) gave Buasso some piano lessons.

For several years his work as a keyboardist took him into the mainstream rock scene in Buenos Aires, before he returned to San Juan to find his former pupil, who is self-taught in opera and jazz, rapidly mastering a unique combination of vocals and double bass. The couple argue about pretty much everything, they laugh – apart from their music, which allows them an almost telepathic communication of notes and space. “It is always a fun process, a challenge,” Buasso says. “He says, can you do that? I say, yes, and it works – always spontaneous, and always a surprise.”