Thorold, Earl Tresham, proud of his ancestral escutcheon, which he claims shows no tarnish, welcomes the proposal of Henry, Earl Mertonn, for his sister Mildred's hand, as it will mean the uniting of two noble houses, he not knowing that Mildred and Henry, who are both very young, ignorant and unguarded, have already met, sinned and now attempt a reparation. He learns from one of his servants that an unknown visitor, who was none other than Henry himself, was seen leaving his sister's chamber, and in a fury of rage sets out to right the wrong as he believes to be the only way.
—Moving Picture World synopsis