SISTERS, uncertain: Mary Wollstonecraft Godwin (Elle Fanning) and her sister, Claire (Bel Powley). Photograph courtesy heraldscotland.com

WHEN THE FIRST thing you do after watching a period drama is to scour the bookshelves to find a particular volume and then secrete yourself between its pages, to gorge yourself on the story and the writing, you know the filmmakers have done something right. This is precisely what may happen to you after you watch Haifaa Al-Mansour’s Mary Shelley with Elle Fanning in the title role. And the book in question? Frankenstein, which the eponymous Mary wrote in 1818, when she was but 21.

The classic tale of a man-made monster is well known and has been corrupted and commercialised in various ways, but this film is about its back story and offers a gloss on the story that is rather unexpected. One could say that Mary Shelley imbibed feminist values with her mother’s milk, but that would be a bit of an exaggeration, as her mother, Mary Wollstonecraft died but ten days after her daughter was born. She was an important proto feminist of the time, however, and brought the young Mary into a world of very particular 18th century values, characterised in part by serious debauchery and rule-breaking.

And it is in this framework that we meet a young and virile poet Percy Bysshe Shelley (Douglas Booth), who wrote great defining works such as Ozymandias, but was also rather a philanderer who followed his passions and cocked snooks at societal values such as marriage and the church. Thus you get to follow a lively but broadly conventional tale of romance and horror stories, heroic milestones and runaways, of late 18th-century style intemperance and general sexual malarkey.

It’s a splendid vehicle for a very able young cast, which also features British actress Bel Powley as Mary’s younger sister Claire and Tom Sturridge as a rather insufferable Lord Byron. But more than that, it’s a tale of loss and sibling love, of jealousy and the horror of abandonment, that will make you reread Frankenstein with a different eye to its context and meaning.

Easy to watch and told with a clarity of narrative, which is satisfying in its predictability, this film arguably retains possibility of reaching classic status, and you can see that, not so much in the dialogue or writing, but in the fervent yet balanced performance of Fanning. It’s a very fine movie that will absorb you from beginning to end.

• Mary Shelley is directed by Haifaa Al-Mansour and features a cast headed by Douglas Booth, Clara Charteris, Stephan Dillane, Elle Fanning, Joanne Froggatt, Ben Hardy, Jack Hickey, Rasneet Kaur, Sarah Lamesch, Hugh O’Conor, Bel Powley, Owen Richards, Tom Sturridge and Maisie Williams. It is written by Haifaa Al-Mansour and Emma Jensen. Produced by Amy Baer, Ruth Coady and Alan Moloney, it features creative input by Amelia Warner (music), David Ungaro (cinematography), Alex Mackie (editing), Amy Hubbard, Heidi Levitt and Katja Wolf (casting), Paki Smith (production) and Caroline Koener (costumes). Release date through Ster Kinekor, Cinema Nouveau: August 3 2018.