eeeAmadscientistgrandfatherinventsagenetictransformationmachineandhis4yearoldgrandsonaccidentallyturnshisbodyintothatofa30yearoldman.BabyBobbyescapesandrunsaroundtownashissiblingstrytocatchhimbeforetheirparentsgetbackfromvacationANDbeforethebadguysgettohimfirst.Themachineisworthalotofmoneyandtheyonlyhaveadaybeforethemachinelosesitscapabilitiestochangebabybobbyback.