The mudlark is Andrew Ray, an illiterate London street urchin of the mid-19th century. Having seen a picture of Queen Victoria on a coin, Ray determines to meet the Great Lady, and to that end he sneaks into Windsor Castle. Victoria (Irene Dunne in a padded costume) has sequestered herself in the castle since the death of her beloved Prince Albert, and has refused to make any public appearances, much to the consternation of Prime Minister Disraeli (Alec Guinness). When the boy breaks into the Queen's sanctorum, her courtiers are convinced he's part of an assassination plot. But Victoria is regenerated by the boy's natural good humor, and for the first time in a long time she emerges from mourning to see her loyal subjects again. Filmed in England, The Mudlark not so much an historical drama as it is an acting lesson from such masters as Irene Dunne, Alec Guinness, and Finlay Currie (as a kilted Scotsman).