It's simple.

If high school nerd and all-round misfit Anthony Michael Hall doesn't hack the Pentagon mainframe in 24 hours, maverick pilot Tom Cruise won't be able to launch his fighter-bombing raid with musclebound, homo-erotic foil Val Kilmer in time to stop half-Russian, half-South African drug dealer Joss Ackland from beating the truth out of battle-hardened Vietnam veteran ex-boxer Sylvester Stallone.

If Stallone cracks then he will blow Eddie Murphy's cover and his white, but borderline-suicidal and strangely accented, rookie partner Mel Gibson won't be able to find the serial killer who's out to assassinate Molly Ringwald before she has time to overcome her teenage angst and be made over from awkward geekiness by her friend Melanie Griffith who is actually her older self who has travelled back in time from the future so that she can ensure that Melanie meets and marries Michael J Fox instead of Emilio Estevez who will grow up to be ruthless Wall Street businessman Michael Douglas.

Molly can only meet Fox at the school prom if Kevin Bacon and Patrick Swayze succeed in teaching him to dance and in stopping the townsfolk from being taken in by superficially well-meaning (but actually bigoted fundamentalist Christian) new mayor J T Walsh who not only wants to close down the steelworks, where welder and nightclub entertainer Jennifer Beals works, but ban dancing throughout the county as well.

Will they make it before the helicopter explodes, killing the cute bear-like creatures who have lived in peace on the wooded planet for centuries, unaware that Chewbacca is their father?