Emma Jane Unsworth has adapted her 2014 novel for the screen and the resulting movie, directed by the Australian film-maker Sophie Hyde, is flawed but interesting, kept upright by the steely core of Holliday Grainger’s performance. It’s an unexpectedly subdued film about the mortality of friendships and relationships, and there is also, as with so many other semi-autobiographical fictions, a subsidiary pleasure in wondering which elements are based on truth.

Laura (Grainger) and Tyler (Alia Shawkat, from TV’s Arrested Development) are best friends who live in Dublin; they’re single, they love going out for cocktails and have developed a kind of sub-Holly Golightly private language about the ironic sophistication of it all. Laura is a would-be writer who has been working on a novel for almost 10 years and Tyler has a dead-end job. The approaching trauma of being in their 30s is worsened when Laura meets an impossibly handsome man called Jim (Fra Fee) who is a talented classical pianist. This creates a Withnail-y loyalty crisis with Tyler, who acidly condemns the outrageously nice and well turned-out Jim as someone with the “shoes of an undertaker and the smile of a despot”.

But it isn’t just Tyler who is thrown into turmoil. With her novel showing no sign of being published, Laura is left to wonder whether marriage – a convention to whose trappings she has been fundamentally indifferent – has turned out to be the endpoint of her whole existence. Will any defiant moment of singledom or hedonism endanger this precious new future, or would it be the last hurrah of youth?

Some of the wisecracking dialogue falls a bit flat and the narrative line is occasionally uncertain, but Grainger creates a watchable quarterlife crisis.