“You’re not supposed to mourn somebody when they are still alive”, contemplates Tusker (Stanley Tucci) when considering the future he has left with partner of 20 years Sam (Colin Firth) in one of Supernova’s many heart-breaking scenes. These are the kind of tragic dilemmas thrown up by Harry Macqueen’s fantastic sophomore feature which tackles the reality of early-onset dementia with grace and honesty. Revolving around the middle-aged couple’s campervan road-trip through the Lake District, Supernova soars thanks to Firth and Tucci’s authentic, heartfelt performances.

The pair’s journey sees them taking in memorable sights from their past and visiting family before a planned comeback gig for pianist Sam. While Macqueen doesn’t make Tusker’s illness immediately clear, it soon becomes apparent something is up when Sam finds a confused Tusker by the roadside after he wanders off during a service station stop. Tusker’s mental capabilities are slowly receding and it’s beginning to affect his own livelihood as he struggles to write his latest novel. With his condition worsening, Tusker considers the difficult options available to him whilst his cognitive abilities are still intact.

SupernovaDespite its bleak subject matter, Supernova never becomes a depressing slog and manages to inject a refreshing amount of humour around its sensitive topic. The film’s biggest joys come from seeing the long-term lovers playfully quibbling, bantering and sharing silly in-jokes while they transverse the picturesque roads of the Lake District. Their rapport is a really engaging one, with Tusker’s sardonic humour complementing Sam’s more restrained character. What could have been quite an ordinary dementia drama is bolstered by Firth and Tucci’s charming, affectionate chemistry.

Both deliver adroit dramatic turns too, especially Tucci who can evoke so much emotion with just a subtle change in facial expression. One poignant dinner-party speech makes for a particularly affecting moment, the duo’s brief glances saying so much with so little.

For the most part, Supernova also manages to avoid over-sentimentality by virtue of Macqueen’s tightly-written script which explores themes of love, memory and mortality with delicate subtlety. Beautiful landscape shots from cinematographer Dick Pope and a suitably moving piano-based score by Keaton Henson also enhance the elegance of the story. While the narrative isn’t anything ground-breaking and follows pretty familiar beats, this sincere portrayal of dementia is unlikely to leave a dry eye in house.