Memento ending explained

What happens

Teddy tells Leonard he already killed his wife's real attacker long ago, that his wife survived the attack, and that Sammy's story is his own. Leonard refuses to accept it, then sets himself a new target: Teddy.

The last image

Leonard, who has just killed Teddy, is shown at the very start of the film, a Polaroid un-developing as the violence runs backward.

What it says

The ending shows Leonard choosing what to believe. He burns the photograph and writes Teddy's plate on a note, so the hunt can continue. The film ends this way to show how people edit their own histories to bear what they cannot accept.