Halloween II is a 1981 film directed by John Carpenter and Rick Rosenthal.
A man who appears to be Michael Myers runs around, and is hit with a police car, which crashes into a truck, causing it to explode and engulf him in an explosion. It is later revealed that the man was not Michael Myers, but Ben Tramer, who was drunk.
Once he realizes Laurie is at the hospital, Michael goes there and kills several people there. Dr. Loomis is ordered back to Smith's Grove, but as a marshall is driving him back, Nurse Marion Chambers informs him of a secret file in Michael that says Laurie is his younger sister, adopted by the Strode family. Loomis forces the marshall to take them back to Haddonfield, and they enter the hospital where the marshall is killed by Michael, who then goes after Laurie. Laurie shoots Michael's eyes out, and Dr. Loomis turns on several tanks of a flammable gas, and then turns on a lighter when Laurie is out of the room, causing the entire room to explode with Loomis and Michael inside it.
Michael walks out of the room, on fire, and collapses, apparently dead.
From here, Halloween splits into two timelines: The 4-6 timeline, with Halloween 4: The Return of Michael Myers as the sequel; and the H20 timeline, with Halloween H20: Twenty Years Later as the sequel. Therefore, Halloween II has two separate sequels.