Our prehistoric foursome are back. Manny, the sarcastic but warmhearted mammoth, finds a mate and is now learning the science of being tactful. Sid, the inept sloth, is trying to establish his long overdue respect from others. Diego, the once shady travel companion now turned loyal carnivore of the ``herd``, must confront a fear that he’s always kept secret. And Scrat the squirrel is still accidently causing shifts in the landscape. But these four have a bigger problem coming when a flood is about to change their history.