It took three actors just 12 days of shooting and a handful of story guidelines to turn director Lynn Shelton's latest - and largely improvised - drama into a charming, moving and witty comedy.
Shelton didn't set out to make her drama about human relationships a funny film. What she did do was put her faith in a small cast who where encouraged to improvise around three-quarters of the film's scenes. This approach and the situations she created for the characters to respond to allow the humour to bubble to the surface through some very real and natural performances.
At the beginning of My Sister's Sister we meet Jack (Duplass) at a memorial for his brother, who died a year earlier. It's clear Jack isn't dealing well with the loss of his brother; and that night he accepts the offer from his best friend, and brother's ex-girlfriend, Iris (Blunt) to go to her father's remote cabin for some time alone.
Arriving at the cabin Jack is surprised to find Iris' sister Hannah (DeWitt) is already there, also nursing a broken heart after breaking up with her girlfriend.
A drinking session later Jack and Hannah end up in bed together, and the real fun begins when Iris unexpectedly turns up at the cabin the next morning.
The set-up for the sibling rivalry is a little forced, mostly when Hannah and Jack first meet, but Shelton keeps the story moving at a pace which forgives any off-pitch moments. What could have been an indulgent talk-fest is tightly reined, and all the conversations that made it to screen really matter.
What's achieved is a real sense of these characters and their motivations. It's amazing how a casual and seemingly innocent conversation around the kitchen table can reveal information that turns everything you previously thought on its head. As the films ends you realise how cleverly Shelton has misdirected your interpretation of the trio's behaviour - Hannah's in particular.
Shelton might not have intended to make a funny film, but she has and Your Sister's Sister is the better for it. The story unfolds subtly and without apparent effort, but it's the humour that provides the warmth and, combined with fabulous and endearing performances, makes this a joy.
Cast: Emily Blunt, Rosemarie DeWitt, Mark Duplass
Director: Lynn Shelton
Running time: 90 mins
Rating: M (Sex scenes & offensive language)
Verdict: A simple, charming and funny talkfest.