A flashback shows the death of Guy's parents when he was a kid. As they drown in tar, they tell him to find somewhere called 'tomorrow'. He goes on a long journey to find it and in the process, meets a young Belt before taking him along for the ride.Some time after the events of the first movie, the Croods (along with Guy and their pets Chunky and Douglas) are still searching for a place to settle down at all while surviving many dangerous creatures along the way. Grug is repeatedly annoyed at Eep and Guy's blossoming romance and it gets worse when he overhears them thinking about settling down together somewhere else away from the Croods. As Grug walks off in anger, he soon comes across a giant wall and leads the whole pack to them. When they bust inside, they see that the wall covers a huge land full of fruits and streams and they believe they have finally found a place to call their home. They are soon caught in a net and are released by the owners of the land, a couple called the Bettermans, Phil and Hope. When the Bettermans meet Guy, they reveal that they know each other from Guy's late parents.The Bettermans welcome the Croods to their giant tree-home as house guests, where they meet their daughter and Guy's old friend, Dawn, who immediately befriends Eep. Life with the Bettermans becomes degrading for Grug due to their evolved lifestyle rubbing off on his family like Thunk getting hooked on watching stuff from their window (similar to a television) and them sleeping in separate beds rather than together and the Bettermans soon reveal themselves to be biased against the cave family because of how destructive they are, believing that Guy is better off with them and hatch a scheme to get Guy to leave the Croods. Phil eventually takes Grug to his secret man-cave (a sauna-like place behind some waterfalls) where he manipulates him into believing Guy should leave their pack. Also, Hope gets on Ugga's bad-side by passive-aggressively saying they should leave while Guy remains with them.Eep and Dawn soon take use Chunky to escape the land and jump their wall for a joyride that ends with a bee stinging Dawn and having her hand swell up. When Eep takes her back home, Guy, upon finding out, chides her for her recklessness, ending with him insensitively calling her a 'cave-girl'. At dinner, tensions rise between the parents, Guy and Eep, especially when Dawn's swelling is revealed. Having enough, the Croods decide to leave in the morning, but Guy decides to stay after he and Eep have a falling out. Soon, the land is attacked by 'Punch-Monkeys' (monkeys with human-like strength) on account of Grug and Ugga eating a bunch of bananas the Bettermans hoard around their land and have forbidden Grug from eating. Phil reveals he sends the Punch-Monkeys the bananas every day so that they leave the Bettermans alone and since Grug and Ugga ate them, the Punch-Monkeys get upset and kidnap Grug, Phil, and Guy and take them to their homeland.As the men are taken, Thunk, Ugga, Eep, Gran, Sandy, Belt, Sash (Dawn's pet sloth), Hope, and Dawn go to rescue them, but eventually get marooned on an island full of Dog-Spiders. During their time together, Hope soon grows to accept the Croods and eventually form a team called the Thundersisters (which was an old girl-group Gran was in when she was younger) to mount a rescue and in the process, Gran revealed that her hair was just a furry bat. At the Punch-Monkey home, Grug, Guy and Phil soon discover that Phil unintentionally deprived the Punch-Monkeys of their water resource and that the Punch-Monkeys need the bananas not only to eat, but to offer to a giant Punch-Monkey in hopes of appeasing it. Since the bananas are gone, they need a substitute. The monkeys make Grug and Phil fight gladiator-style to see who will be the sacrifice and when they wear each other out, they exchange their bitter feelings with each other, making Guy regret what he said during his and Eep's fallout.Soon, the monkeys dress all 3 men as bananas to sacrifice to the giant Punch-Monkey. Grug and Phil apologize for their poor behavior and for putting pressure on Guy, but just as they are about to be eaten, the Thundersisters show and to rescue them. A long and perilous battle soon ends with Guy and Eep on a giant skull-chandelier where they reconcile and soon use it to defeat the giant Punch-Monkey by using fire to cut the ropes and send it falling into the abyss below when it catches Eep's 'peanut toe' (which she uses as a prosthetic limb) and pulls it off, allowing the families to escape.With their differences finally settled, the Bettermans allow the Croods to live in their land as neighbors, with Guy realizing that Eep is his 'tomorrow' and he and Eep soon move into one of the Betterman's bedrooms together and Grug finally accepts his daughter leaving with Guy.