In late 1951, Eilis Lacey (Saoirse Ronan), a young Irish girl, emigrates to Brooklyn. Sponsored by Father Flood, a priest from her native town Enniscorthy, she is assured to find a full-time job there. But the early days are tough, seasickness being soon replaced by loneliness and homesickness, two feelings all the more acutely felt by Eilis for having had to leave behind her widowed mother and her dear sister Rose. She nevertheless little by little manages to find her footing by adapting to her job as a salesgirl, by studying bookkeeping at Brooklyn College as well as with a little help from both Father Flood and Mrs. Kehoe, the owner of the boarding school she now lives in. And not only does graduation follow but love shows its face in Tony, an Italian-American plumber, full of adoration and respect for her. They end up marrying, although keeping the thing secret. It is at that point that tragedy strikes: Rose suddenly dies. Which incites Eilis to return to Enniscorthy, in order to share her sorrow to support her mother morally. And there a strange thing happens : she gradually gets lured by the charms of her native place, going as as to let herself be wooed by Jim Farrell, a young local.