The plot is diabolically simple: two stranded American tourists are given shelter by a famed German doctor (a maniacally intense Dieter Laser) who made his fortune surgically separating conjoined twins.  Now his mad genius is pushing the doctor to do the reverse.  He tells the women that they will be surgically attached to a Japanese businessman-mouth to buttocks, one after the other-and thus will be born a new creature.  The human centipede!  Compellingly perverse, hilarious and shockingly straightforward!