The sprawling kingdom of Takicardia finds itself under the ruthless reign of King Charles V + III = VIII + VIII = XVI, a monarch who is as despised by his subjects as he is reviled. This merciless ruler harbors a passion for hunting, albeit hindered by his unfortunate cross-eyed condition. Of course, no one would dare speak of this flaw in his presence, as his palace is adorned with countless statues and paintings that portray him with perfectly aligned eyes. Occasionally, however, he does manage to strike his mark—much to his chagrin, it is often the wife of a bird, the titular l'Oiseau. Serving as the narrator, l'Oiseau relishes in mocking the king at every given chance.
Within the confines of his hidden apartment, the King harbors dreams of a beautiful shepherdess whose portrait graces his wall. However, this enchanting figure is in love with a chimney sweep, whose loathed image hangs directly opposite. As night descends, the enchanting paintings burst to life, yearning to escape the palace, only to be hunted down by an animated version of the King, who is notably devoid of his cross-eyed dilemma. This doppelgänger usurps the real King and commands the capture of the shepherdess and her beloved sweep, but fortunately, the clever bird is always lurking nearby, ready to assist.
In time, the shepherdess and the chimney sweep find themselves wandering through the darker alleys of the lower city, a place that has never basked in sunlight. Meanwhile, the cunning King calls forth a robot of his own design, launching an assault on the village. Seizing the shepherdess and imprisoning the chimney sweep, alongside the bird and a blind organ-grinder from the village, the King demonstrates his ruthlessness by placing the organ-grinder among fierce lions and tigers. In a desperate twist of fate, the King coerces the shepherdess into an engagement by threatening the chimney sweep's life. Under duress, she acquiesces, after which the King commands the chimney sweep and the bird to churn out sculptures of his head on an assembly line. However, the two dare to spoil the King's creations, resulting in their imprisonment.
In jail, the organ-grinder captures the attention of the lions and tigers, and the bird persuades these fierce creatures to aid the shepherdess, highlighting the dire consequence of her union with the King—her neglect of the sheep, a delicacy for the animals. This passionate plea ignites a thrilling escape, leading the creatures to rampage against the King and his minions in the chapel. Seizing control of the robot, the bird and his progeny commence a full-scale demolition of the castle.
As dawn breaks over the debris-laden ruins of the castle, the robot notices one of the bird's offspring trapped in a cage, leading to a heartwarming rescue where the bird is freed, and the cage is crushed underfoot. Interestingly, while the movie has its roots in "The Shepherdess and the Chimney Sweep," it diverges significantly to focus on the intricate relationship between the King and the bird, alluding to the essence of Andersen’s fable. In this retelling, the shepherdess and chimney sweep are represented as china figurines, a deviation from the film's artistic portrayals.
The film culminates in a joyous ending as the bird captures a photograph of the newlyweds—the shepherdess and chimney sweep—surrounded by the King’s dog and the entire flock of the bird's sons, celebrating their victory after the king's downfall.
