Little Grunt brings home a very large egg for a special Sunday brunch; however, in the middle of the night, the egg opens up to reveal a baby dinosaur.
A boy, living in the ancient world before the invention of drawing, creates the world's first pictures as a means of sharing his visualization of everyday objects with those around him.
When a dinosaur hatches from the egg that Little Grunt brought home for dinner, Mama and Papa Grunt let him keep it as a pet until it grows too big for their cave.
When a cave man's spear breaks while fishing, his daughter composes the world's first letter and sends it home to her mother requesting the delivery of a new spear.