Buckaroo Banzai Michael Gonzales and his mentor Dr. Hikita Matt Bugielski perfect the "oscillation overthruster", a device that allows one to pass through solid matter. Banzai Mike tests it by driving his Jet Car through a mountain. While passing through it, Banzai Mike finds himself in another dimension, and on returning to his normal dimension, he discovers an alien organism Beau Callies has attached itself to his car.

News of Banzai's Mike's success reaches Dr. Emilio Lizardo Sam Wizer, currently held at the Trenton Home for the Criminally Insane. In 1938, Lizardo Sam and Hikita Matt had built a prototype overthruster, but Lizardo Sam tested it before it was ready, and became stuck between dimensions. Though freed, being stuck between dimensions caused him to go insane. Aware that Banzai Mike has succeeded in passing through that same dimension, Lizardo Sam breaks out.

Later, Banzai Mike holds a press conference about his rocket car experience, the overthruster, and the specimen of alien/transdimensional life Beau he obtained while traveling through the 8th dimension. Strange men disrupt the event and kidnap Hikita Matt. Due to an electrical shock from an unknown source, Banzai Mike sees these men as reptilian humanoids and gives chase, managing to rescue Hikita Matt before being discovered. Banzai Mike manages to evade the men long enough to be rescued by his allies. ​