It's a South Korean comedy about an old lady who gets rejuvenated. She's fifty years younger. This film was a box office smash, getting at least nine remakes across East Asia and beyond. These include China/Taiwan and Vietnam in 2015, Japan and Thailand in 2016, Indonesia in 2017, the Philippines and again China (this time as a TV series) in 2018, India in 2019 and Mexico in 2022. A Hollywood remake has also been optioned, but don't hold your breath.

Our heroine, Oh Mal-soon, is played by Na Moon-hee (age 74) and Shim Eun-kyung (age 20). As an elderly widow, she's shameless and appalling. We empathise, but she's still a vulgar battleaxe who physically attacks a customer at the cafe where she works, tells strangers what they're doing wrong and is driving her daughter-in-law to a heart attack. She treats old age as a license to behave badly. She spoils her son and her grandson, but towards other women she's disdainful.

...and then, as a 20-year-old, she's the same. Bloody hell, she's rude. This is funny and cringeworthy. She'll grope boys' bottoms, or make tasteless jokes about penises. Shim Eun-kyung is great (an ex-child star in her first role as an adult actress), wonderfully embodying a dreadful-but-likeable old woman.

The comedy's strong. Mal-soon jumps to conclusions, behaves inappropriately and gets suspected of killing herself. She also becomes a singer and gets involved with what's initially a heavy metal band. (Seeing death metal guitarists doing 1950s "doo-wop" backing vocals might be the film's funniest joke.) There's potential romance, with love interests for both her old and young selves. (Trying to handle that situation could break anyone's brain.) Underneath all that, though, is heavyweight emotional material. Mal-soon's husband died before their baby was born and she raised the child as a single mother in the 1960s and 1970s, sometimes making ruthless choices. The film got to me in the flashbacks to Mal-soon's past, and in a scene towards the end with 20-year-old Mal-soon and the son who's now much older than her. Or, of course, in the blood transfusion.

This film is cute and charming, but also capable of being sharp and even brutal in that way I associate with Korean cinema. Sometimes, it's silly. (Well, the concept doesn't suggest kitchen sink realism.) I'll be watching the Japanese remake tomorrow, but this original definitely earned its success.