The lion Alex (Ben Stiller) is the king of the jungle, and the number one attraction in Central Park zoo in New York, where he lives in perfect harmony with his friends: the zebra Marty (Chris Rock) the girrafe Melman (David Schwimmer) and the hippopotamus Gloria (Jada Pinkett Smith).
Captive from the beginning, the four friends fill themselves with destiny and do not weary themselves of the new public ... But Marty would again want more. Pushed by an insatiable curiosity they manage to escape with the assistance of a band of Penguins and launch themselves into a world of discovery which is new to all of them.
The lion''s three partners are terrified to join him, but are quickley reassured and find themselves on a vessel destined for Africa. When the irrepressible Penguins sabotage their floating prisons, Alex, Marty, Melman, and Gloria find themselves on the exotic shores of ... Madagascar.
And so begins for these four natives of New York, an adventure in the rough apprenticeship of the true jungle…