John Doe needs to get information from (or kill) Richard Roe. Unfortunately, Richard Roe has just been thrown into prison. How to get access to someone surrounded by high walls, barbed wire and armed guards? Why, commit a crime and get imprisoned yourself! After all, escaping should be easy for our hero once the deed is done!
Undercover police officers do this in real life, but in fiction they go [...] [tvtropes.org]