 Martin needs to rush to Mexico as a treasure chest that has just been discovered has a tablet inside marking Martin s arrival on Earth during the Aztec era, the tablet complete with a carving of his likeness. He needs to get there before anyone opens it and discovers his Martian origins. Tim decides to accompany him just in case. They find the chest, which is scheduled to be opened at a big festival the following day, in the Police Chief s office, the Police Chief who is guarding it. They run into a further problem when Martin s antenna won t go down, the symptom caused by an excessive consumption of peppers. They solve the two problems with a simple sombrero covering Martin s head and a diversion to get the chief out of his office. Martin gets the tablet out of the chest and disappears just as the chief returns to the office, leaving Tim to deal with the chief. The one problem beyond telling a convincing story to the chief of why he s in the office is the fact that Martin s antenna didn t disappear when he did, thus leaving a "floating" pair of antenna. The fact that his antenna won t disappear means that Martin s ailment has reached a critical stage, that he will eventually go invisible forever except for his antenna. He remembers just in time that a certain mineral contained in the chest is an antidote for his ailment, luckily this remembrance just as the chest is to opened.