Zany foursome Errol, Herman, Tacio, and Peewee geared up for a short underwater dive towards Hundred Islands when a series of miscalculations cause them to resurface on the shores of Mexico. As they try to reorient themselves for their homebound dive, a dying man entrusts them with a battered sombrero which happens to be coveted by loony adventurer Lastiko and his formidable henchman Alagua.