Writer Diablo Cody and director Jason Reitman combine forces yet again, rounding out their unofficial trilogy exploring the lives of women. While Juno tackled a teenage girl facing womanhood, and Young Adult examined the narcissistic mindset of a stunted thirty-something, Tully explores the messy, overwhelming nature of motherhood.

Charlize Theron is remarkable as Marlo, a mother of two young children and a new baby, Mia. Marlo isn’t the usual type of mother represented onscreen; she’s neither a halo-shining image of maternal goodness (any Jennifer Garner role) nor the strikingly beautiful “average” mom who complains just enough to be endearing (hello Leslie Mann). Marlo is exhausted and angry, emotional and raw. Her useless husband (Ron Livingston) escapes on business trips, while Marlo, still carrying her baby weight, feels out of control and imprisoned by both her life and body.

Until Tully arrives. Tully, played by the fantastic Mackenzie Davis, is a night nanny, whose job it is to ensure Marlo gets some actual sleep. Wise, empathetic and sexy, the 26-year-old is not just a balm in Marlo’s chaotic life, but a reminder of how confident and free Marlo herself used to be.

Reitman and Cody are a serious cinematic force. The director’s use of immersive montages portrays Marlo’s stress and sleep deprivation as a child-led conspiracy, until you viscerally feel her pain and frustration, while Tully’s scenes exude the character’s assured calmness. Meanwhile, Cody’s script is brimming with the dark humour that is her trademark, capturing Marlo’s genuine, often terrifying despair and the joking way she minimises her pain in order to survive.

The screenplay’s quirkiness can undermine the very real issues on display. It’s implied that Marlo’s son may be on the autism spectrum, but this is soon abandoned, while Marlo’s post-partum depression also gets some questionable – but never questioned – treatment.

What makes Cody and Reitman powerful is their desire to explore the awkward and uncomfortable issues – but one wishes they had just a little more courage to dig deeper.

Directed by Jason Reitman. Starring Charlize Theron, Mackenzie Davis, Mark Duplass, Ron Livingston, Emily Haine.