Originally meant as a sequel to the Super Mario Land games, Wario Land eventually proved popular enough in its own right to launch its own series.
Wario, having been kicked out of Mario's castle in his first appearance, decides, in his eternal greed, to search for a statue stolen by the nefarious Captain Syrup and the Black Sugar Gang. Along the way this would normally involve the occasional side quest for hidden treasures and collecting as many coins as he can possibly amass.
Here, however, Wario decides this isn't worth his time and proceeds as quickly as possible towards the final confrontation - going so far as to skip entire levels and otherwise make a mockery of the game engine.