Sam and Tusker, romantic partners for 20 years and amateur astronomers, undertake a road trip in a campervan across England to the Lake District, to visit some of their favourite spots and for a reunion with friends and family.

The couple spend their second night on the edge of a lake they had visited together 20 years ago, in the early days of their relationship.

Later, on a walk through the woods, Sam tries to talk with Tusker about near-future adjustments they'll need to make on their home and his intention to stop performing, but he refuses to hear about it.

He also discovers that Tusker has a vial of pentobarbital and has made a farewell audio tape, explaining that he intends to take his own life.

In the final scene, Sam appears on stage, playing the beautiful piano piece that Tusker loved so well.

In October 2019, it was announced Colin Firth and Stanley Tucci had joined the cast of the film, with Harry Macqueen directing from a screenplay he wrote, with StudioCanal distributing in the United Kingdom.

[9] In October 2020, Bleecker Street acquired U.S. distribution rights to the film[10] and released it in the United States on 29 January 2021.

Critics consensus on the website reads, "Led by moving performances from Colin Firth and Stanley Tucci, Supernova is a heartbreaking look at the emotional toll that comes with accepting mortality.