Twelve (2001)

Twelve follows Zach, a club kid who awakens with amnesia in a friend's apartment. He has no memory of his past – not his identity, friends, enemies, family, or even his own name. He begins a disorienting quest to piece together his life, initially assuming it's a consequence of a night of partying. But unsettling feelings of unfamiliarity lead him to question everything he thought he knew about himself. Zach must now uncover a hidden life he's been living, a life that is now unknown even to him.