Mrs. Brown is taking a course on how to be a private detective, and her first assignment is to prepare a dossier on an unsuspecting person. Her choice of subject is Martin. Of course, Martin knows what she's up to, but he is still a bit concerned about her discovering his Martian identity. Mrs. Brown finds Martin's flight log, which is written in Martian, but again Martin is concerned since the uneducated are too dense to know any better. She takes a photograph of it, which Martin is worried she will pass onto authorities, who, when they are unable to decipher it, will suspect him of being a foreign spy. She apparently has mailed the film to her teacher, J. Nathaniel Pierce, who is more shyster than teacher. Martin needs to apprehend the film before Pierce gets a hold of it. At Pierce's office, Martin searches to no avail, and must endure a sales job by Pierce before he finds out that the mailman can't and won't deliver Mrs. Brown's film since she failed to put postage on the package. From there, it's a an easy task of levitation for Martin to get the film and ultimately protect his identity. For Mrs. Brown's own safety, Martin tries to talk her out of taking the course since she will be facing brutish criminals. She heeds his advice: instead of quitting the course however, she decides to protect herself by also taking judo lessons. (thetvdb.com)