It's basically expected that good triumphs over evil in movies and TV, because it's generally what mainstream audiences want to see.
But of course not all stories are going to send the same message, and sometimes good just doesn't win - or, if it does win, it's only at the cost of the hero's own life.
The latter option is an especially daring and risky one to take in a TV series, where viewers have potentially invested dozens upon dozens of hours in a story, only for the hero to be offed, often by the villain of the piece.
This can be tremendously unsatisfying when it isn't executed well, but when it works, it can bring an entirely new emotional dimension to a story and the journeys of both the hero and villain.
It's a twist that's likely to be divisive, but when it works, it really works.
These 10 TV shows all dared to have the hero die at the villain's hand, whether to pass the torch to a new hero, to subvert the audience's well-trained expectations, or ensure the series as a whole went out with a bang...
10. House Of Cards
House of Cards' first season firmly established Congressman Frank Underwood (Kevin Spacey) as a ferocious villain to be reckoned with, a man who would kill to ensure his ascendancy to the White House.
It also blatantly positioned hungry young journalist Zoe Barnes (Kate Mara) as Frank's inevitable foil, with audiences expecting that Zoe would eventually expose Frank's crimes to the world.
But the show had other ideas, namely having Frank murder Zoe in the season two premiere, meeting her at a Metro station and pushing her in front of a train.
It was a supremely shocking moment, taking the established hero character and suddenly killing them with a shocking flippancy.
To rub salt in the wound, Zoey's colleagues never end up getting justice for her death despite knowing Frank was responsible - they either die themselves or go into hiding.
Worse still, the only real "winner" at the end of the show is Frank's near-equally Machiavellian wife Claire (Robin Wright), who following Frank's sudden death in the final season becomes the last person standing as the unchallenged President of the United States.