The premise is that with some crimes, the best way to catch the original perpetrator is to decant a clone with their memories and tell the clone they have 4 days to find the original or they die. This seems like an odd backdoor method, but after that it's a decent action story. Oh and everyone also is infused with nanites that heal them and "theme" what they see. "Theme" being the term for altering perception to make everything perfect. Despite lots of words focusing on the main character (the clone) being motivated the the original killed their husband (this was the crime) that emotional aspect never really landed for me.