原开人咕噜一家六口在老爸Grug（尼古拉斯·凯奇 Nicolas Cage 配音）的守御下糊口。每天掠取鸵鸟蛋为食，躲藏野兽的追击，每晚听老爸阐述同一个故事，在山洞里过着一成固定的糊口。年夜女儿Eep（艾玛·斯开 Emma Stone 配音）是一个和老爸性情截然相逆的充斥益奇心的女孩，她不满脚一辈子留在这个幼山洞里，专心想要追逐山洞理论的天下。
Grug：Cave! Everyone inside! Come on! Hurry up! Let's go! Let's go! Go! Go!
Ugga：No more caves, Grug.
Gran：We're gonna jump on the sun and ride it to Tomorrow with Guy.
Grug：Wait, wait, so you're all going to do this? Thunk?
Eep：You have to stop worrying for all of us.
Grug：It's my job to worry. It's my job to follow the rules.
Eep：The rules don't work out here!
Grug：kept us alive!
Eep：That wasn't living, that was just... not dying. There's a difference.
Grug：Ugga, everyone, you have to listen to me!
Eep：We'd be dead now if we'd listened to you! We have to follow Guy now.
Guy：This is pointless! We've running out of time! Everything is collapsing. You are being irrational and counterproductive.
Grug：Big words anger me! Keep talking!
Guy：Countermeasures! Remember how you were this morning? You changed, remember? Idea man? Modern man?
Grug：I am a caveman!
Guy：No, no, no, wait!
Grug：No! What is this stuff that's saving you from my punches?
Grug：No! I have to get back to them!
Guy：You have to stop...Stop struggling!
Guy：Grug, stop! No one gets out of this. Believe me. I know.
Guy：I was little when it happened. The last thing my parents told me was: "Don't hide. Live. Follow the sun. You'll make it to Tomorrow."
Grug：You followed the light. My daughter is a lot like you.
Guy：No. She's like you. She loves you but always forgets to say it, just like you forget to tell her.
Grug：I guess I was just busy keeping them all alive.
Guy：It's okay. That's what dads do.
Grug：That's right, and we can't do that from here. We need one of your ideas. Come on, you can do it.
Guy：Belt! Emergency Idea Generator, activate.
Grug：I've got it.
Grug：Yeah. I know, but, he's doing the best with what he has. Let's go. There he is.
Guy：Belt, I want romance, drama, sincerity. Move me. Okay, he sees us! That's our cue. Now work it! He's not coming over. I don't think out puppet looks scared enough.
Grug：Scared? I’ll show you scared! Hand me those acting sticks!
Grug：Yes! You did it!