The Robinson family is jettisoned into space aboard the Jupiter 2 space ship, piloted by father, John and made homely by mum, Maureen. The family includes children; Will, Penny and Judy along with a handsome co-pilot, Don; a robot who thinks for himself and a dastardly but often likeable saboteur named Dr. Smith. Their mission is to colonize a new planet but a meteor storm throws them off course. Now, no matter where the Robinsons venture, they discover diabolical trouble, amid an amusing array of aliens, cyborgs, creatures, space pirates, black holes and freakish phenomena, to which the robot constantly bellows, "Danger Will Robinson!"