When mad scientist Henry Hassel discovers his wife in the midst of committing adultery, he decides that simple murder would be intellectually unsatisfying; he therefore builds a time machine with the intention of killing his wife's grandparents in their youth, so that she will never have existed. When he returns to the present, however, nothing has changed. In a desperate attempt to alter history, Hassel begins killing historical figures of greater and greater significance (eventually including Mohammed, thus the story's title), only to learn that the nature of time is very different from what he had thought.
Connie Willis described it as "very funny" and one of her favorite time-travel stories (while misattributing it to Harry Harrison),[4] and Jo Walton categorized it as "excellent" and "thought provoking", and specified that it is "(v)ery clever, very funny, and quite chilling when you think about it."[5]