The story runs in the 1940s Mexico City. A schoolboy (Carlos) falls in love with his best friend's mother (Mariana). Carlos is impressed because this family is not like the ordinary mexican families of the time, because they have many expensive American things, although they are not rich. The drama begins when Carlos gets out of school to go to declare his love to Mariana, and is discovered by his teachers.
Test pilot Tuck Pendleton volunteers to test a special vessel for a miniaturization experiment. Accidentally injected into a neurotic hypochondriac, Jack Putter, Tuck must convince Jack to find his ex-girlfriend, Lydia Maxwell, to help him extract Tuck and his ship and re-enlarge them before his oxygen runs out.
Veteran buttoned-down LAPD detective Roger Murtaugh is partnered with unhinged cop Martin Riggs, who -- distraught after his wife's death -- has a death wish and takes unnecessary risks with criminals at every turn.