In 1986, Margaret Humphreys (Emily Watson in a sterling performance), a British social worker, meets Charlotte (Federay Holmes), a desperate Australian woman who is trying to locate her mother in order "to find out who I am." Shortly afterwards, Margaret encounters Nicky (Lorraine Ashbourne) who is on a quest to locate her brother Jack (Hugo Weaving) whom she was separated from when they were children. Looking into both cases, Humphreys discovers a secret project during the 1950s through the 1970s in which thousands of English children were yanked out of orphanages or taken from "unfit" mothers and illegally deported to Australia. These bewildered kids were told that their parents were dead and the move was "for their own good." Margaret is outraged at the dire effects this had upon these children who felt abandoned and unloved. Promised sunshine and oranges, they ended up growing up in institutions.

Margaret begins to research the deportations, even using her vacation days to go Australia. To her surprise, her boss suggests that she make this her main work. Suddenly hundreds of deportees are asking for help. Humphreys is fortunate to have a husband Merv (Richard Dillane) who takes care of their kids and patiently and lovingly supports her even when the project takes over most of her time and causes a great deal of stress.

Over time, Margaret is able to reunite many families and her availability in Australia becomes well known. She learns that many Catholic children were sent to an orphanage run by the Christian Brothers; the little boys were abused, beaten, and used as slave labor to build a monastery. After hearing about this, Humphreys suddenly starts receiving threatening calls and break-ins at her office in Australia. But she also has earned the respect and loyalty of many others, and Jack, who has been reunited with his sister, comes to guard her. Another man, Len (David Wenham), had initially been suspicious of her motivations but changed his mind after she helped him locate his mother. When Margaret nearly buckles under the stress of the suffering she is hearing, he turns out to be a wounded healer for her.

Jim Loach, the son of social justice filmmaker Ken Loach, directs this passionate drama about one woman's expose of a scandal that eventually rocked two countries, resulting in apologies in 2009 and 2010 from the Australian and British Governments; some 130,000 children were part of the forced deportation programs. The literate screenplay by Rona Munroe is based on the book Empty Candles by Margaret Humphreys. In the film, this social worker is portrayed as a top-notch researcher, a patient and persistent crusader for her cause, a courageous woman who overcomers her fears by walking through them, an empathetic listener who gets burnt out for a while, and a motherly figure who wins the love and allegiance of the people she helps.

There are few movies around these days that introduce us to genuine heroines able to rise up in the moment to improve the lives of others. Margaret Humphreys compassionately helps others in the Great Work of a lifetime: finding out who you really are!