Margarita captures a turning point in the life of a Canadian family. Power-couple Gail and Ben have all the visible advantages of two successful careers – a beautiful home, vacations and a nanny for their teen-aged daughter, Mali. Inside the beautiful home, however, a creeping complacency has left the once idealistic couple disconnected from their dreams, from their child and from each other. On top of this, some amateur investing has left them just about broke.

At the centre of their new reality is Margarita, the young Mexican nanny, who has been working and living in Canada illegally for the past six years. Passionate, resourceful and devoted, Margarita's role has gradually shifted from nanny to that of housekeeper, cook, maid and care-giver to the entire family. While single-handedly raising Mali, she has been quietly making ends meet, stretching the family's taut resources in creative and industrious ways.

Life is not all work and no play for Margarita. The Latina has a passion for life and people. She throws groovy hot tub parties for a posse of outrageous friends and flirts mercilessly with hunky Brazilian handyman Carlos who clearly worships the ground she walks on. But, she's already in love. The object of her desire is Jane, a shy, commitment-phobic law student, who, although she clearly loves Margarita, is hesitant to bring their relationship out of the shadows.

Somehow oblivious to their dependence on her, Gail and Ben decide that Margarita's small salary stands between them and financial stability. They fire Margarita, setting in motion a chain of events that leads to an immigration investigation and a deportation order. Heart-broken and disillusioned, Mali withdraws further from her parents, forcing them to finally take an honest look at the state of their relationship and their family.

The well-meaning, but hapless couple, now desperate to keep Margarita in the country, cook up a phony marriage scheme. Carlos, who truly loves Margarita, also offers to marry her. As each of these options involves some further degree of servitude, Margarita decides to return to Mexico. Although there is nothing left for her there, it is the one place she can truly be free. On the eve of Margarita's departure, Jane arrives with the one proposition that could change everything.

In the guise of a family drama, Margarita looks, through the eyes of a hard-working illegal, at social injustice as it relates to class, race and immigration policy. With warmth, humour, and candour, Margarita also tells the story of the disillusionment, resentment and alienation that inhabit the margins of our closest relationships.