It all starts in the castle, where you can choose which of the five cities (Rome, Nairobi, Beijing, Moscow, San Francisco) to start the game. The player controls Luigi, brother of Mario.
The latter, incidentally, villainous plans are much more ambitious - the flooding of the planet Earth through melting of the Antarctic ice instead of a kidnapped Princess. Oddly enough, but in the name of the fit is not the whole story - Mario ate some of those chocolates and was confined in the castle of Koopa (the main antagonist of the series). However, the first game with Luigi in the lead role has gained any kind of popularity (even if it came out on multiple platforms, including already beginning to rot the NES console) and the PC was released as a floppy version and the CD reissue with a strange voice (Mario speaks with a pronounced Italian accent, and Luigi - no). In many reviews of it (and Mario's Time Machine and Mario's Early Years) were compared with the well-known series of educational games about Carmen Sandiego, and obviously not in favor of the former. Mario is Missing! - quite an interesting educational app for the famous mascot of Nintendo's plumber Mario.