Colin Firth and Stanley Tucci shine in a drama that cuts you to emotional shreds

Cert tbc, 93 min. Dir: Harry Macqueen; Starring: Colin Firth, Stanley Tucci, Pippa Haywood, Peter Macqueen, James Dreyfus  

Science tells us that the elements found inside the human body have been thrown across the universe to Earth by dying stars. But when the hour arrives for one of us to burn or flicker out, what, if anything, do we give the universe back? That question lies at the heart of Supernova, the immensely tender, sad and uplifting second feature from the British director Harry Macqueen, which premiered at the San Sebastián Film Festival this week. It follows a middle-aged gay couple on a driving holiday in the Lake District, shortly after the course of their lives has made a turn for the worse.

Tusker (Stanley Tucci), a dapper and deeply personable author, has been diagnosed with young-onset dementia. And this means that Sam (Colin Firth), his partner, and a moderately well-known, taciturn pianist, is steeling himself for the years if not decades of caring ahead, all while the man he fell in love with fades from sight.

For now, they’re coping, just about. Tusker occasionally finds himself unable to alight on the right word – but then the two have been together long enough to be sunk in that strange kind of romantic forgetfulness, where one can refer to virtually any object under the sun as “the thing”, and the other know exactly what they’re talking about. Even so, when a term as simple as “triangle” eludes Tusker, he grows vexed, and tries to suppress his frustration by pawing at his chin – both Tucci and Firth’s performances are alive with such subtle, lived-in gestures; they don’t just make for a personable couple, but also an extremely plausible one.

The pair are travelling in their trusty old camper van, but have two stops planned along the way. One is at Sam’s old family home, where his sister Lilly (Pippa Haywood) lives with her husband Clive (Peter MacQueen) and their daughter. The other is at a remote cottage – a couple of nights away for just the two of them, plus their (adorable) dog, dovetailed with a recital Sam is giving in a town nearby. It’s a journey on which both men must bid farewell to old possibilities, and which they cannot complete without accepting what lies ahead.

Their story is simple at heart, and also familiar, having been told on film with great gentleness and insight a number of times before. (In 2015, Julianne Moore won an Oscar for her work in Richard Glatzer and Wash Westmoreland’s Still Alice, in which the patient was also a person of letters – a linguistics professor, rather than an author.) But what distinguishes Supernova isn’t the particular course of Sam and Tusker’s relationship so much as the relationship itself, which feels utterly honest and real, and also wonderfully familiar, even after we’ve enjoyed just half an hour of their company on screen. It isn’t long after that that Tusker attempts to give a speech at a family dinner party – but after struggling to make sense of his own words, he hands the pages to Sam, who reads them aloud on his behalf.