Mary Carpenter goes to the seashore for a change in air. Peter Cooper, a wealthy young idler, arrives at the same hotel. Both Peter and Mary have grips bearing the same initial, a large “C,” and careless bellboys mix the two so that when Peter arrives in his room and proceeds to unpack, he discovers amid a quantity of dainty lingerie, ponderous volumes on the “Planets” and “Advanced Astronomy,” by a Prof. Carl Von Munsternberg. Remembering the pretty girl he saw registering, he returns the grip to the desk after slipping in a best seller, “The Road to Love,” that he has been reading en route. At the same time Mary arrives with his grip, in which she has found an assortment of pipes and pajamas. When Mary returns to her room and discovers “The Road to Love” she is at first indignant, but soon starts to read it. Peter, meanwhile, meets in the lobby a young widow who has long set her cap for him, and knowing she will lay in wait for him, he tries to devise some scheme for meeting Mary and avoiding the widow. He finds Mary next day seated on the sand reading the book he gave her, but she pretends not to see him. Thereupon he determines to disguise himself as Prof. Von Munsternberg so that she will take notice of him. He has a number of cards printed bearing the name of Carl Von Munsternberg, Doctor of Astronomy, University of Carlsbad. Disguised, he returns to the beach and drops one of his cards near her. Picking it up, she believes he is the great professor, and engages him in conversation. Next day Peter, in his disguise, finds Mary awaiting him. He tells her that he wants her to test “The Power of Attraction.” He asks her if there is any one upon whom she wishes to fasten her “thought vibrations.” She mentions a certain young man in the hotel, and he tells her to concentrate her thoughts on him that evening. Peter dances with the widow that evening. He sees Mary following the professor’s instructions, calling Peter to her, that is, mentally. Peter stops dancing and leaves the widow. He goes to Mary and asks her if she called him. Mary is overcome and cannot answer him, but turns and goes to her room full of excitement at her apparent success. Meanwhile the real Prof. Von Munsternberg has arrived from Carlsbad. The guests at the hotel agree to take a boat trip. The real professor is invited to take the trip with them. The widow with her jewel case, the detective who has been engaged to watch the jewels and the sneak thief, who hopes for an opportunity to steal them, all embark. Peter in the astronomer’s guise, also sets sail likewise. Mary looks out for Peter, who seems to be nowhere in evidence. Peter, however, in his professional disguise takes Mary aside and talks to her of the stars. Top Munsternberg overhears him, and much amused at his astronomical ignorance, inquires his name. Peter produces one of his cards. The professor reads his own name on it, and decides that Peter is a dangerous impostor. The thief, meanwhile, has managed to creep into the widow’s stateroom and secure the jewels, which he hides under his coat, but fearing a search, he slips the jewel box into Peter’s telescope box. The widow discovers the theft, while Peter and Mary are star-gazing. The widow hurries to the detective, and the real Von Munsternberg, overhearing their conversation, is now confident that Peter is the thief, tells them of the impostor, and they decide to search him. While they search the bag and find the jewels, Von Munsternberg tears off Peter’s false whiskers, and to Mary’s horror, it is Peter who stands before her. No sooner have the jewels been set down, when the thief creeps up and steals them. As they are handcuffing Peter the widow catches sight of the thief diving from the side of the boat and they all start in pursuit. Peter begs for permission to go in pursuit also. This is granted, and he dives after the thief, captures him, restores the jewels to the widow, explains to the group the real reason of his prank, and they forgive him, all but Mary. It is not until he has convinced her that it was his only chance of winning her that she yields to forgive him.