After ten years of "love-hate relationship", the pigs and birds are still "undermining each other" as usual. However, the "uninvited guest" launched ice balls to attack Bird Island and Pig Island, forcing both sides to put aside their grudges. The former hero of Bird Island, Fat Red, joined the bird friends and formed a temporary alliance with the former rival "Naughty Pig" Leonard and his group. They will go to the new frozen island to stop the mysterious villain's plan to destroy the world.