In Oranges and Sunshine, Margaret Humphreys (Emily Watson) repeatedly insists that her mission to uncover the truth behind a mid-20th-century U.K.-to-Australia child-migration scheme isn't about her but about the victims, but Jim Loach's docudrama is very much centered on this unflappable social worker. An almost self-consciously staid recreation of Humphreys's mid-1980s efforts to bring light to a national atrocity, the film is so careful to avoid the luridness that would seem inevitably to accompany an excavation of child kidnapping, forced labor, and rape, that the result is a plodding, overly tasteful procedural that holds up its hero as an incorruptible embodiment of goodness.
As she journeys from her home in Nottingham, England to Australia to investigate a forced labor scheme that sent English children from "bad families" to work camps Down Under in order to build churches, Margaret discovers more and more details about the scheme that implicate increasingly influential figures. Naturally, these figures are less than thrilled about her investigation and, equally naturally, given the heroicizing nature of Loach's film, Margaret works up a perpetual tone of righteous indignation, but all this moral superiority seems mighty easy in the retrospect of half a dozen decades.
Loach and screenwriter Rona Munro complicate the story somewhat by introducing several conflicted victims with whom Margaret develops a relationship and who illustrate the complex feelings experienced by people who were unwittingly raised by church officials toward their captors. Similarly, under increasing threat for her physical safety, Margaret's former unflappability starts to wane until she begins to suffer a breakdown, though these sequences are forced to rely on some jarring and particularly clumsy horror-movie tropes such as showing menacing figures lurking outside windows.
Eventually, Loach plunges us into the inevitable heart of darkness, intercutting Margaret's trip to the church building that the children were forced to build with snippets of victim testimony revealing the horrors they suffered. Even here, Loach withholds much in the way of lurid detail (though we're certainly meant to be appalled by what we do hear), instead relying on a strained bit of juxtaposition to keep us both outraged and distanced from the historical truths he and Margaret are uncovering. In the end, the latter's efforts may have proved momentarily futile, at least in effecting any immediate official recognition of the scheme, but, in a key moment, one of the victims assures her that what she's doing is more than enough. Sufficiently vindicated, Margaret can remain the unquestioned hero of a film whose ostensible purpose, confirmed by the inevitable factoid-filled closing title cards, is to bring light to formerly under-recognized atrocity.