For a school video project, Josh and Kenlyn decide to investigate the egg industry. Their assignment is to find out how the egg industry has changed over the years, where it is today, and come up with a conclusion as to why the industry has changed.

Scrat is still trying to nab the ever-elusive nut and in the process may find his true love; Manny and Ellie await the birth of their mini-mammoth; Diego, the saber-toothed tiger, wonders if he's growing too 'soft' hanging with his pals; and Sid the sloth gets into trouble when he creates his own makeshift family by hijacking some dinosaur eggs. On a mission to rescue the hapless Sid, the gang ventures into a mysterious underground world where they...