The odd item from the given options is "Metre".
Explanation:
Plot, theme, subject are all related to literature, whereas metre is a term associated with poetry. Metre refers to the rhythmic structure of a poem, which is determined by the arrangement of stressed and unstressed syllables in each line. On the other hand, plot refers to the events that make up the story, theme refers to the central idea or message conveyed by the story, and subject refers to the topic or content of the story. Therefore, since metre is not related to prose writing or storytelling, it is the odd item in this list.