Under Scrum, we have a story which was estimated to be quite short. Once the story was picked up by a developer, it turned out that a significant amount of technical preparation is required, and this is dragging hugely.
The business has agreed that the preparation work can be left as it is once we reach the end of the sprint, so that the developer can continue to pick up other (more important) work - meaning that the story cannot be done. This is an explicit agreement with the business that the current story will be picked up later (after a particular deadline has passed.)
Should this problematic story be moved to Done, marked as cancelled and then resurrected in a later sprint or should we simply mark it as blocked and leave it where it is until some (possibly much) later sprint has capacity to pick it up?
A third option is that we dissect the story into two: one for the preparation work and one for the actual work. But with that the question remains: What should be done with the actual story, given agile guidelines?