From Netflix:

Suffering short-term memory loss after a head injury, Leonard
Shelby (Guy Pearce) embarks on a grim quest to find the lowlife
who murdered his wife. To carry out his plan, Shelby snaps
Polaroids of people and places, jotting down contextual notes
on the backs of the photos to aid in his search and jog his memory.
A gritty, complex thriller, Memento packs more knots than
a hangman’s noose.

When this violent movie came out, people would argue for
hours about what happened in the movie. It is not an easy
movie to understand, but if you like puzzles, this is a
(violent) movie for you.

Pay attention,