LEGO City Undercover isn't quite the Grand Theft Auto game everyone was expecting, but it's the closest thing you'll ever get to playing a LEGO minifig in a relatively open world that's not unlike Liberty City or San Andreas.
Like all of the titles in the Grand Theft Auto series, the world of LEGO City Undercover offers a main quest line, a host of sidequests, and a whole bunch of optional things for you to find and uncover. The game clearly borrows a lot from its spiritual predecessor as well as titles in the LEGO series of games.
If you should ever find yourself stuck in any part of the game, the following walkthroughs should come in very handy and serve to unstuck you from whatever mission you're having trouble with.