Murphy, who has just purchased a new high hat, is invited to the wedding of Kelly. He goes and during the excitement he leaves his hat on a chair. A large, fat woman sits on the chair. The hat is sent out by the groom and fixed. Murphy and Nolan plan to play a joke on Casey and put his hat on the chair. They are trying to persuade the fat woman to sit on it when Casey enters, sees the joke, and substitutes Murphy's hat for his own. The fat woman is then placed on the chair. Murphy asks Casey out for a walk and Casey consents. Murphy takes a hat from the piano and finding it too small discovers that it is Casey's hat. He pulls the fat woman from the chair and finds his own, flattened worse than before. Filled with rage, he rushes out, takes all the other hats and stamps upon them. The guests are about to attack him when Casey, who is the only one with a whole hat, plays an Irish jig on the piano. At the sound of Erin's music, all hat is forgotten, and a dance begins.
—Moving Picture World synopsis