Scientists studying protein structures using X-ray crystallography often face a problem: flexible parts of proteins don’t show up clearly in their images and get left out of molecular models. This paper demonstrates a new technique called ensemble refinement that can visualize these ‘invisible’ flexible regions by creating multiple model versions simultaneously. Using a mushroom enzyme that produces psilocybin as an example, researchers show that this approach reveals how protein parts actually move and change shape, providing better understanding of how proteins function.