Until the House Un-American Activities Committee horned in, several postwar Hollywood films dealt with touchy "liberal" subject matter. Lost Boundaries stars Mel Ferrer as a light-skinned African-American, whose family is "passing" in an all-white New England community. When the truth comes out, the more bigoted neighbors demand the expulsion of Ferrer and his family. Considered pretty potent stuff in 1949, Lost Boundaries appears fairly conventional today, especially in its reluctance to cast a genuine black actor in the lead.
by Hal Erickson synopsis