I saw a commercial for a television show called “Timeless”, the premise for which is apparently that some malevolent person has stolen a time machine and is trying to use it to change history and destroy the country. So the protagonists are “saving” the country by undoing whatever changes are made. But what if the change initiator has no ill intent. They are going to stop the Hindenburg from crashing, or get a ticket on the Titanic to keep watch for iceburgs, or introduce the germ theory of disease centuries earlier all to save lives and help people. But to maintain temporal continuity, the “time police” have to prevent (or undo) these changes. A philosophical anti-hero doing the ‘right thing’, but would people still consider them to be a “good guy”?