Spoiler Warning: This film is inspired by a true story, so many viewers will already know the outcome. The reviewer has attempted to avoid explicit plot spoilers, but just discussing the film's themes means you may guess at plot twists.
Philomena is based on Martin Sixsmith's book The Lost Child of Philomena Lee. Steve Coogan plays Sixsmith, who is smarting as the film begins. He recently lost a prestigious journalism job, and believes his firing was unfair and unwarranted. But no matter where he goes, nobody appears to be interested in his side of the story.
Philomena Lee (Dench) is in a similar situation. When she was nineteen, she was forced into indentured servitude to pay for the shelter and care that the Irish nuns provided her, and now, fifty years later, she is haunted by curiosity about the son who was taken from her. Philomena has contacted the orphanage she worked in several times, but all she know is that all records have been lost. They reminded her that she signed a document surrendering parental rights and promising not to attempt to contact her child.
So Sixsmith agrees to use his reporter skills to help Philomena locate her son. In return, he'll get access and the right to publish the human interest story he believes could get his career back on track.
This is an actor's piece, and both leads are tremendous. There's probably not an adjective in the thesaurus that hasn't been deservedly laid at Dench's feet, and Coogan is right there with her in what is arguably a more difficult—certainly a more unlikeable—role. Philomena rambles cheerfully about romance novels and is enthralled by cable-access movies in upscale hotel rooms. Sixsmith is disdainful of her provincialism ...