On paper, the synopsis of Grandma reads as if the film was created with the express intention of annoying the right- wing moral mavens at Fox News. A crisis-pregnancy comedy – uh, oh – featuring Lily Tomlin as Elle, a retired lesbian poet whose granddaughter Sage (The Perks of Being a Wallflower's Julia Garner) needs an abortion. Laverne Cox, the transgender star of Orange is the New Black, has a supporting role as a tattoo artist.

Before anyone reaches for their placard of choice, Grandma is rather more complicated than its pitch – or its anti-arse- numbing run time – might suggest.

The prospect of termination is not, despite occasional outbursts of pro-choice bravado from the eponymous heroine, taken lightly by either of the two women, who head off in Elle's creaky 1955 Dodge Royal (Tomlin's own) in order to raise the funds required. Their adventures take in forgotten feminist subcultures, Sage's ne'er-do-well ex-boyfriend, one of Elle's bruised old flames (Sam Elliott) and multigenerational friction: Sage has never heard of Betty Friedan's The Feminine Mystique; Elle doesn't know who Mystique from X-Men is.

Mostly, this is a stealth study of grief: Elle has not, despite the romantic interest of a younger lover (Judy Greer), come to terms with the loss of her partner of 40 years, and her loss is trumpeted in outbursts of misanthropy and scorn. When we finally met Sage’s mom (Marcia Gay Harden), we realise that this was a family trait even before the loss.

Paul Weitz, the co-creator of American Pie, wrote the clever, consistently funny, surprisingly affecting script especially for Tomlin, who hearts back with one of the best performances of the year.