Now that he's all grown up and no longer embarrassed about being unable to sing like the rest of his kind, Emperor Penguin Mumble (voice of ELIJAH WOOD) now has a chick of his own, young Erik (voice of AVA ACRES), with his mate, Gloria (voice of PINK). Due to Mumble's previous behavior, their tribe now sings and dances, but little Erik can't do either and is embarrassed when he tries. Accordingly, he runs off with fellow chicks Atticus (voice of BENJAMIN FLORES JR.) and Bo (voice of MEIBH CAMPBELL) who've decided to follow Adelie penguin Ramon (voice of ROBIN WILLIAMS), who's tired of being rejected by the female penguins, back to his tribe in another part of Antarctica.
There, Ramon tries to impress Carmen (voice of SOFIA VERGARA), but finds himself in the shadow of outsider Sven (voice of HANK AZARIA), a penguin who can actually fly and encourages all others to believe in themselves and follow their dreams. Another creature who's dreaming big is Will (voice of BRAD PITT), a krill who's grown tired of being at the bottom of the food chain and has decided to eat his way up it, much to the chagrin of his pal, Bill (voice of MATT DAMON).
Once Mumble finds his son and the other two chicks and starts them on their journey back home, he tries to dispel the whole "if you dream it you can become it" notion that's now in Erik's head. But he must also contend with an obstacle in their way, a huge elephant seal by the name of Bryan the Beachmaster (voice of RICHARD CARTER), as well as climate change causing parts of their world to melt.
In fact, the latter has gotten so bad that by the time Mumble and his young entourage return home, they find their land now surrounded by giant and unscalable cliffs, much to the concern of Gloria, Atticus' dad, Seymour (voice of COMMON), everyone else, and their leader, Noah the elder (voice of HUGO WEAVING). Realizing everyone will perish if they don't get help, Mumble allows Bo to get Ramon, his friend Lovelace (voice of ROBIN WILLIAMS), Sven and the rest to mount an effort to feed and rescue the trapped penguins.