Nintendo has been widely criticized for this fairly dull game. It is primarily educational; Luigi collects pieces of famous landmarks and learns about geography in the process.
In the introductory sequence, Mario falls through a hole and Luigi must find him. There is little to no plot.
The gameplay consists of moving around a town in side-scrolling manner while jumping on koopas to collect artifacts (pieces of famous landmarks). Luigi then must take artifacts to their respective locations and correctly answer three questions about the landmark. Once all three artifacts have been replaced, Luigi must determine what town he is in to get Yoshi. He then can then proceed to another town to do it all over again.