Director Lone Scherfig (An Education) returns to the Festival with this rousing romantic comedy set in Britain’s wartime film industry. Featuring a cast teeming with some of the UK’s most charismatic comedic actors, Bill Nighy and Richard E. Grant among them, Their Finest is about boosting morale in a period of national — and personal — crisis.

Catrin Cole (Gemma Arterton, who also appears at the Festival in Orphan and The Girl With All the Gifts) is a “slop” scriptwriter, charged with bringing a female perspective to war films produced by the British Ministry of Information’s Film Division. Her current project is a feature inspired by stories of British civilians rescuing soldiers after the retreat at Dunkirk. Catrin’s artist husband looks down on her job, despite the fact that it’s paying the rent. At least lead scenarist Tom Buckley (Sam Claflin) appreciates her efforts.

While on location in Devon, Catrin begins to come into her own and earn the respect of her peers. She’s the only crewperson that Ambrose Hilliard (Nighy), a past-his-prime yet nonetheless pompous actor, will talk to.

Based on the novel Their Finest Hour and a Half by Lissa Evans, the film pops with witty banter and flows with lovely period detail. The characters are uniformly textured and the performances nuanced. Nighy is perfectly cast in his endearingly withering role, and Jeremy Irons turns up for a delicious cameo. It is, however, Arterton’s show. She brings subtlety, intelligence, and a range of beautifully gauged emotions to Catrin, whose path to self-renewal is an inspiring example of a talented woman forging her place in the world.