在这部怪奇!鬼胎缠身恐怖片中,ホラー映画の脚本執筆が思うように進まず、スランプ中の脚本家・梅木(池内万作)。梅木は臨月を迎える妻の秋子(有坂来瞳)と定期検診のため、産婦人科に行った。その時、梅木の脳裡に突然湧いてきた素晴らしいイメージ!それはトカゲを身篭る夫婦の話だった。妻の妊娠中に不謹慎だ、と叱られながらも、梅木は作品の出来にとても満足。評判も上々だった。しかし…、現実に生まれてきた赤ん坊は半分爬虫類という、梅木の脚本よりもグロテスクないきものだった。不気味な液体を排泄しながら、床を這いずり回る半爬虫類の赤ん坊。その赤ん坊を、母親としての情愛でいとおしく腕に抱く秋子。映画の撮影が順調に進む脚本の世界と酷似してゆく現実に困惑し、錯乱状態に陥った梅木はある恐ろしい行動に出る。
Horror screenwriter, Umeki, has writer's block. He goes with his pregnant wife, Akiko, to a check-up and is struck with an incredible idea - a horror story about a woman who gives birth to a reptile! Despite his wife's disgust, Umeki goes ahead with the screenplay, which the critics love. But the horrible prophecy fulfills itself, as his wife gives birth to a freak of nature. His baby is born half human, half lizard! The reptilian baby slithers on the floor, leaving a wet trail of slime behind [it]. To his horror, his wife, Akiko, holds it lovingly in her arms. His movie has become a mirror image of his own life as Umeki slips slowly into madness...."