Dave is a Nestrian, a clumsy, silly-looking, brightly coloured creature whose only skills are making comfortable nests and secreting a foul smelling cloud of gas whenever he gets scared for his live. Dave is constantly moving around searching for a place to stay, a real home, much to the dismay of Finny, his son, who only wants to make friends.After hearing a rumor of a colossal wave that is said to cover the whole world, Dave packs up again and takes Finny to a giant gathering of animals. Where their only salvation awaits, a huge ark, big enough to fit all the animals of the world built by a very nice human called Noah.Unfortunately, Dave and Finny are turned away as theyre not on the Lion's list who manages all animals affairs on the ark. But it takes more than that to dissuade a Nestrian.With the use of some creative thinking, some Nestrian craftsmanship and the involuntary help of the carnivorous Grymps, Hazel and her daughter Leah, they manage to sneak on the ark after all.Just when the day seemed to have been saved, Dave and Hazel realize that Finny and Leah have disappeared. Their curiosity having gotten the better of them, they were on the scaffolding as the tidal wave hit the boat it sailed away.The parents panic as the ark sails off leaving their children stranded on the last bit of land not yet engulfed by the water.Their desperate race against time begins. Leah, who is a born hunter and survivor is burdened with the clumsy and awkward Finny, but somehow they manage to escape from the rising water and the greedy and gruesome Griffins. Eventually they add two more odd creatures who were also rejected from the ark to their ranks. Finding his footing, surrounded by his new group of friends, Finny starts to emerge as the brave hero that he really is.Meanwhile their parents must get over their differences to work together, fight their way through gorilla guards and the vain and ruthless Lion to take control of the ark and save their children.Having done many adventures, the "fearless four" (Leah, Finn, Obesy and his parasite companion) manage to fight off the continuing attacks of two griffins who see Leah and Finn as their dinner. The gargoyles are eaten by Obesy who falls in the sea some time later. As the water reaches the top of the mountain where Lea and Finny are, the parents manage to take control of the ship and steer it to the mountaintop. Leah and Finn manage to climb on a piece of floating ice when the water engulfs the mountain.When the ark passes their little iceberg, it turns out to be hard to climb on. Finny first manages to climb on the ark but does not want to leave Leah behind and jumps back on the iceberg. Then Leah jumps on board of the ark and uses her sharp claws to hold on. Finny tries to get back on the ark too, but falls in the water, seemingly unconscious or dying.When Dave tries to save Finny from drowning in the water the plot twist is revealed: Nestrians are really water creatures, perfecly able to breathe and swim while submerged. Obesy turns out to be a whale. This also explains why Dave was never feeling at home.In the final scenes Dave and Finny swim alongside the ark, waving at leah and Hazel. On the deck of the ark the lion captain and his flamingo assistant discuss whether they should have told Dave and Finny in the beginning they were sea creatures.