For most of us, the experience of waking up in a strange motel room, alone and disoriented, means that you were the victim of Chinese Organ Thieves. Inconvenient, sure, but kidneys are replaceable.* And how often does it really happen?** For Leonard Shelby, however, this scenario was just another part of his daily routine.
You see, Leonard suffers from a rare form of amnesia, usually only found in protagonists in works of fiction. Unable to form any new memories, Leonard stumbles around Southern California, vowing after every meal that he will never eat a McDonald's Filet-O-Fish again. To be fair, he does have a slightly more pressing agenda than eating pre-formed patties of vague seafood: the attack that rendered him an amnesiac also resulted in the death of his wife. Through an intricate system of tattoos and notes to himself, he hopes to one day track down the killer and after making him beg for mercy, ask them who they are, why he has this gun and if they know directions to the nearest McDonalds.
Also, at one point in time during the movie, a peripheral character muses that Leonard’s condition must be like living your life backwards. Despite this being a barely coherent thought muttered by a bearded motel attendant, it's evidently license enough to tell you the entire story in reverse, making this Mike, Kevin and Bill's first ever xarTffiR!
*Just talk to the delivery guy from the Chinese food place down the street
**Every time you order from that Chinese food place