Thomas Parnell, better well known as Tommy, was the son of Pumpkinhead, deformed due to being spawned from a demon and presumably a mortal woman. Tommy was murdered by the Red Wings auto club in Ferren Woods in 1958. 35 years later, he is resurrected with a body similar to his father's by a group of teenagers who accidentally hit Miss Osie with their car. Tommy, in the form of Pumpkinhead, would then set out to kill all of the Red Wings and the teenagers responsible for the fire at Osie's shack.
In 1958 in the country town of Ferren Woods, Tommy is ruthlessly and brutally killed by a group of drunken teenagers of an auto club called the Red Wings. 35 years later, another group of teenagers, one of which is the son of one of the same Red Wings members who killed Tommy, attempt to awaken Tommy's corpse, which they find after accidentally hitting an elderly woman with their car, who turns out to be the woman who once took care of Tommy while he was alive. After the teenagers leave due to a fire started at the old woman's house, Tommy's corpse begins to morph into a Pumpkinhead-like creature, and it is later revealed that the creature attempted to save the old woman from the fire.
Tommy then sets out to avenge his murder by killing all of the former Red Wings members and marking the kill scenes with wing-like symbols using the creature's own blood. It is also later revealed that Tommy was actually the son of the Pumpkinhead demon, presumably spawned from a mortal woman, hence Tommy's deformity.
The following night, Pumpkinhead kills a local farmer named Ernst (another former Red Wings member) by disemboweling him while caught on a pig-scouring hook. The next night, Pumpkinhead kills another former Red Wings member, leaving his less-than-wise girlfriend in severe shock. The last of the Red Wings members to be killed before Judge Dixon, the mastermind of Tommy's murder, are the Knox brothers. 4/5 victims so far.
At the local hospital, the old woman who was caught in the fire is revealed to be Miss Osie, and she explains to Sheriff Sean Braddock that she looked after Tommy before he was killed by the Red Wings before she dies as a result of severe injuries from the fire. Tommy somehow senses her death.
Tommy eventually finds and kills Judge Dixon after breaking into his home and marking the walls with more blood wings symbols. Before he is killed, Dixon somehow recognizes 'Pumpkinhead' as Tommy, and in pure shock and terror, repeatedly exclaims "it can't be you". Dixon's head is then crushed by Tommy off-screen.
With all 5 of the Red Wings killed, Tommy then sets out to kill all of the teenagers who awakened him and set Miss Osie's shack on fire, first killing three of them and then going after Danny (Dixon's son) and Jenny (Sean Braddock's daughter).Pumpkinhead painfully rips off Danny's head and then goes after Jenny, chasing her to the iron mine where Tommy was killed by the Red Wings. Sheriff Braddock arrives and shows Pumpkinhead the necklace that was given to him by Osie before she died, and also reminds him of the time he saved Tommy's life at the iron mine when he (Braddock) was a boy. Recognizing Braddock and knowing Jenny is his daughter, Pumpkinhead sets her free.
Judge Dixon's posse arrives, who he had called for earlier before he was killed by Pumpkinhead, and begin shooting the creature. Pumpkinhead's death is a repeat of how Tommy was killed, and the creature is eventually dropped into the iron mine. Dying in the exact same place and In (mostly) the same manner.
It is very interesting to note how very unique and different Tommy Is rom the original Pumpkinhead. Tommy's body is actually venerable to weapons and physical harm. Being able to be harmed with guns. The original Pumpkinhead's body is completely immune to physical harm. Tommy is also the only demon to actually show some form of mercy. As he set Jenny free after realizing that she is Sean's daughter. Ms. Osie (the equivalent of a summoner in the film)'s death did not physically stop or even harm Tommy. He also expresses feelings of rage and grief after she dies. Making him the only demon to posses any such feelings for their summer.