自由公園裡的小動物們逐漸習慣了依賴堅果店生活，每天玩樂，慢慢失去了動物生存本能。松鼠安迪為此深感憂慮，而松鼠蘇爾利卻覺得輕鬆過日子沒有什麼不好。直到某日，堅果店發生爆炸意外，失落的小動物們回到公園決定重新開始，卻又發現公園即將被貪婪的市長改建成遊樂園。驟然失去食物來源及家園，小動物們頓失依靠，無比絕望。在拯救被市長女兒擄走的巴哥犬寶貝的行動中，蘇爾利的莽撞行為導致好朋友巴迪身受重傷。經歷了這麼多，蘇爾利終於懂得反省自己的莽撞。小動物們也逐漸發現夥伴的重要性，以及原來生活終究還是要靠自己的努力。在蘇爾利的帶領之下，小動物們決定向貪婪的人類選戰，奪回家園。
炎熱的夏天過去，枝上的樹葉慢慢轉成紅色。中央公園內，松鼠、浣熊們發現過冬的堅果根本不夠用，這群小動物可能面臨前所未有的飢荒。松鼠塞利（威爾·阿奈特Will Arnett 配音）和安迪（凱瑟琳·海格爾Katherine Heigl 配音）奉命前去尋找堅果，它們計劃打劫一輛堅果車，誰知卻造成了一場大混亂，也導致好不容易的手的堅果毀於大火。在此之後，塞利遭到流放，只有他的老鼠朋友巴蒂（Robert Tinkler 配音）自始至終跟著他。另一方面，安迪則和自我感覺良好的同伴格里森踏上尋找堅果的旅程。最終，安迪和塞利在一座庫藏豐富的堅果店重逢，而那裡的幕後老闆竟然是一個臭名昭著、窮兇極惡的罪犯。
螳螂捕蟬，黃雀在後，犯罪者策劃新的劫案同時，卻不知有一群小動物正準備打劫他們…
After breaking out of a rehabilitation zoo, Frankie, a squirrel with all the angles, returns to his forest. He learns from his dim-witted best friend, Cody, a porcupine and street-con, that while he was in lock-up, the entire forest was picked clean by The A.C.O.R.N.S. Institute (Alternative Cosmetic Oils for Regenerative Natural Skin-care). No acorn was left behind. With winter just around the corner, it's a potentially devastating blow to all forest critters. So, Frankie has no choice but to bust into the brand new, state-of-the-art, rodent-proof A.C.O.R.N.S. Processing Plant and take back all of the acorns! Though a seemingly impossible heist, success would not only save the lives of his forest friends, but it would also give Frankie a chance to win back the love of his life, Lola, a local "show squirrel." Sadly, Lola has been burnt by too many of Frankie's false promises in the past.
When Petra spends an evening with her best friend Sanna, Sanna asks how she knew she was bi. Petra tries in earnest to show her the truth.
A man tragically falls into bad company and ends up busting out.