Isabel Green Maggie Gyllenhaal is stretched thin by a life that never seems to slow down: managing a bustling farm, keeping the village shop afloat, and tending to three lively children—Norman, Megsie, and Vincent—while her husband Rory Green Ewan McGregor fights in the Second World War. The weight of responsibilities compounds when the Greens’ quiet countryside is disrupted by the arrival of Cyril and Celia, their wealthy city cousins who are evacuated to the farmhouse. The clash between country simplicity and urban snobbery sets the stage for daily frictions, louder than any wartime din.
Enter Nanny McPhee Emma Thompson, a magical, unorthodox guardian who lands in the Green home just as tensions peak. At first, the children resist her, their quarrels and bravado echoing through the kitchen and fields. Yet her gentle mischief and peculiar rules begin to soften the hardest hearts, and the farm steadies as if under a spell, though the magic remains practical and quietly transformative rather than flashily spectacular.
Meanwhile, the family’s precarious finances are threatened by Phil Green Rhys Ifans, Isabel’s brother-in-law who has gambled away his share of the land and is pursued by two hired women acting for a casino magnate named Mrs Biggles. Phil’s schemes grow mean and petty, the kind meant to force Isabel into selling yet again. He even plays a cruel card by releasing a litter of piglets to a neighboring farmer, hoping the act will force a hand in the settlement. The children uncover his plan, and their teamwork deepens the bond among them as they rally to protect what matters most to the family.
A show of gratitude leads Isabel to organize a countryside picnic, a moment of shared peace that is abruptly interrupted when Mrs Docherty’s ARP Warden husband warns of bombs and the war’s reach into every corner of their lives. Amid the fear, Phil receives a telegram claiming Rory has been killed in action, shattering Isabel’s confidence and throwing the household into distress. Yet the youngest members of the Green clan, especially Norman [Asa Butterfield], insist that their father is not gone, and Norman holds fast to a belief held “in his bones” that his dad might still be alive.
To uncover the truth, Cyril [Eros Vlahos] and Norman persuade Nanny McPhee to accompany them to London’s War Office, where Cyril and Celia’s father, Lord Gray [Ralph Fiennes], holds a powerful position. Lord Gray’s stern exterior meets a more human moment as Cyril calls out his parents’ distance and neglect, prompting a quiet reassessment. Norman’s suggestion that Phil forged the telegram forces Lord Gray to dig deeper, and the truth begins to come into focus as the adults confront the deception.
While the older siblings are away, Megsie [Lil Woods], Celia [Rosie Taylor-Ritson], and Vincent rally to halt Isabel’s signing of Phil’s papers, crafting playful diversions—like pretending a mouse is scurrying in the kitchen—to delay the perilous decision. The crisis escalates when a German pilot drops a bomb on the barley field; the blast doesn’t explode, but its force smudges Phil’s incriminating papers with ink, a small stroke of luck that changes the trajectory of the crisis.
Returning home, Nanny McPhee, Norman, and Cyril witness Phil’s confession, and Isabel decides he must answer for his lies. Phil is restrained, and the community breathes again. As the Greens endure the danger, Mr Docherty bravely defuses the bomb, and Megsie, aided by her siblings and Nanny McPhee’s jackdaw Mr Edelweiss, helps bring the situation to a safe close. The harvest of barley resumes under a calmer sun, with the magical touch of Nanny McPhee guiding the process, and she gently slips away when her presence is no longer required.
The film reveals a tender reveal: Nanny McPhee departs as the family realizes she is not meant to be permanent, a surprising return of Agatha from the first film in baby form, Agatha. With the threat behind them, Isabel and the children rush outside to greet Rory, who returns with a bandaged arm and a heartfelt reunion that mends the family’s rifts. The home is again a sanctuary, and the war’s shadow begins to lift from their little world.
In a lighthearted post-credits moment, Ellie the elephant—summoned by Nanny McPhee to share Vincent’s bed—enjoys a peaceful, whimsical moment with a Scratch-o-matic, a magical invention that keeps the mood bright even after the dust of recent trials has settled. The Greens’ resilience, the kids’ cleverness, and Nanny McPhee’s quiet, practical magic come together to affirm that love, family, and a little enchantment can weather the harshest storms.
