For Agent J, it is another day at the office, monitoring, licensing and policing all alien activity on Earth. One day, J receives a report of an unauthorized landing of an alien spacecraft near New York. It is an old enemy of MIB, a Kylothian named Surleena. Who is searching for a powerful artifact called The Light of Zartha. J investigates and quickly realizes he is going to need help. Unfortunately, the other MIB agents do not work up to par like J can. So, J decides to bring back K. J must bring back K's memory as an MIB agent and try to stop Surleena, before she can succeed.