A motif is like having a favorite toy that you always play with. In a story, it's the same idea - there's something that keeps showing up over and over again. It can be a symbol, an object, a character trait, or a theme.
For example, in the story of Cinderella, the motif could be the glass slipper. It's something that keeps coming up throughout the story - it's how the prince finds Cinderella, it's what she loses when she runs away from the ball, and it's how the prince proves she's the one he's been looking for.
Motifs help add depth and meaning to a story. They can represent different ideas or emotions, and they give the story a sense of continuity. So even though the plot might be moving forward, the motif reminds us of something important that ties everything together.