Men In Black II: Office post

Whats happening in this movie clip Agent J (Will Smith) finds Agent K (Tommy Lee Jones), who doesnt remember anything of his life as a Men in Black agent. J tries to tell him but K thinks hes crazy, until he sees that everyone working in the post office with him are aliens. Rent or buy Men in Black II here: Whats the movie about Agent K (Tommy Lee Jones) has retired and had his memories erased. However, Agent J (Will Smith) needs his help on a case.