Two parents meet with a genetic counselor to discuss the traits their genetically engineered child will have once it's born. The counselor walks through the traits they have selected and assures them that all "prejudiciously biased traits have been eradicated."
Peter gets home after being bitten by a genetically-engineered spider during a school field trip. He falls ill from the spider's venom, and while he's asleep the venom alters his genetic makeup. He wakes up to find his body has changed dramatically overnight.