Herman Hamburger is an awkward fellow with a passion for science. Herman has been building a time machine for several months in the basement of his home. One day he receives his final part by courier, a green dental chair that will seat the time traveler. The chair turns out to be smaller than what he thought he had ordered, requiring him to make some quick adjustments to his design. Herman eventually completes the unusually small time travel device, and sits in it, hoping to travel to the period when the Great Pyramids of Egypt were being constructed. He launches the machine and following some loud bangs and puffs, he is disappointed to find his time travel device has failed to take him anywhere. Herman gets up from the chair and walks upstairs to the kitchen where he left his family to clean up after dinner. He finds that the house is completely empty. After becoming concerned, Herman decides to contact the police. As he is about to pick up the phone, the door bell rings. A mailman hands him a letter which, much to Herman's surprise, is addressed 'To Dad.' After opening the letter he finds it is dated the year 1945. Herman quickly realizes his time travel device has sent, not him, but his entire family through time. He must now figure out how to get them back home safely, in present day time.