Donald Lowrie, a popular young businessman, has been misunderstood in his casual attentions to Vivian Conroy, who assumes a proprietary interest in him, which becomes amusing to their friends. Dick and Elsie Martin, a young married couple, are entertaining their cousin, Marian Wayne. Upon her introduction to Donald, the mutual attraction between Marion and Donald is so pronounced as to call forth the exhibition of violent jealousy on the part of Vivian. In the brief period of her visit, Marion is thrown constantly into the society of Donald by her friends, much go Vivian's discontent and Donald's satisfaction. They soon become engaged and smothering her disappointment, Vivian is forced to congratulate them. Unconquered, however, Vivian still schemes to secure Donald for herself. She pays a society actor to attend a reception to which all the young people are invited. While Marion is placed in a position where she can see all that goes on, the actor, Arthur DeLysle, impersonating Donald for a moment, caresses Vivian among the shrubbery and Marion listening, hears Vivian address words of endearment to the supposed Donald. An estrangement results. Marion flings back the ring to Donald. Vivian cheers him and marries him. Later on, DeLysle, the actor, goes broke and demands money of Vivian. She pays him, but realizing that she has not made Donald happy, she feels guilty. In the meantime, Marion goes into charity work and meeting Carl Lambert, a kindred spirit, agrees to marry him through she tells him of her real love for another and of her disappointment. Before the marriage can be performed, DeLysle blackmails Vivian again. She refuses to pay him; he assails her and in the ensuing struggle, she receives a mortal wound. Almost with her last effort she writes two letters of confession, to Marion and to Donald. She is forgiven; there is a reconciliation between Marion and Donald and a new joy dawns at the end of the rainbow of hope.