Durante la noche de Halloween, Michael, un niño de seis años, asesina a su familia con un cuchillo de cocina. Es internado en un psiquiátrico del que huye quince años más tarde, precisamente la víspera de Halloween. El psicópata vuelve a su pueblo y comete una serie de asesinatos. Mientras, uno de los médicos del psiquiátrico le sigue la pista.
Sinopsis en inglés:
The year is 1963, the night: Halloween. Police are called to 43 Lampkin Ln. only to discover that 15 year old Judith Myers has been stabbed to death, by her 6 year-old brother, Michael. After being institutionalized for 15 years, Myers breaks out on the night before Halloween. No one knows, nor wants to find out, what will happen on October 31st 1978 besides Myers' psychiatrist, Dr. Loomis. He knows Michael is coming back to Haddonfield, but by the time the town realizes it, it'll be too late for many people.