A material designed to be uncuttable has been invented in England. Called Proteus, instead of focusing on the material’s hardness, researchers made the material able to wear down the cutting tools, making it impossible for them to be penetrated.
The material is a combination of aluminum and ceramics. In a nutshell, as the material is cut into, fine ceramic particles fill the material’s structure on the cellular level, which helps it harden. These ceramic particles cause the cutting tool to deteriorate instead or penetrate.
The only issue is that the cutting tool can get some penetration before the ceramic particles can stop their progress. This short video shows what looks like the blade making progress into the material, but it’s the blade being worn down.
Turning this into a story, what if this material was used to make the safe in a heist story? The beginning could be the standard heist, complete with the entourage of professionals with varying skill sets, and they succeed with their theft of the entire safe midway through the book.
This is when the story could take a twist. There is literally no way to get into the safe. It turns into a cat-and-mouse story, with the detectives hot on their trail and limited ways to transport the heavy safe in the first place.
One by one, the members of the team are taken into custody until the very end. The safe owner then shows up to confront the last remaining team member, who plans on destroying the safe and its contents and living far away and under the radar.
The safe owner says he was wondering how durable it was, and together they submerge it into molten iron (like in Terminator 2).
Later, the last member of the heist team is taken into custody. He witnesses the now-solidified iron being cut away, and the door of the safe exposed. They open the door and inside is a single dollar.
The story would be told from the viewpoint of the last man standing. This is supposed to be his last job before retirement.