Since the last piece of the alien device can not be retrieved, Jim must literally use his head in a possibly deadly experiment to try to power up Roy's device in a desperate attempt to save Earth from the alien invasion.
Jim goes to see a doctor about his giant head. After seeing strange lights in the sky one night, he woke up with this condition. On his way home, he's attacked by a gang and he finds out what's inside his head.
The fourth piece of the device is discovered in a small hick town by the locals, who, not knowing what it is, turn it into a tourist trap by likening it to the Arthurian legend of the sword in the stone.
Roy convinces Jim to go on the date he was suppose to have with the girl he likes. It turns out she's into Reservoir Dogs. However, another alien lands on Earth and he's not a friendly type.
Jim joins a support group that helps people with strange bodily conditions. However, Roy is about to be lynched at the Statue of Liberty and calls Jim telepathically for help.