A man named Stanley (Carrey, Dumb and Dumber) is a hardworking banker, one night while driving home his car breaks down on a bridge. He gets out of his car and looks over the bridge and sees what he thinks is a body in the water, he rushes down there in hopes of saving the man, but it turns out that its just a mask. He brins it home, he was very close to putting it on but didn't. The next night he tries it on, and as it turns out the mask fits perfectly, his whole face turns green and he goes wild, he meets this beautiful girl Tina (Cameron Diaz). Later on he ends up robbing a bank, he gets caught the next day...not knowing what hen had done the night before. Later he gets out of jail, thanks to his dog. He saves Tina from the bad guys, and he swares he will never use the mask again, so he put it back where he found it.