In outer space, the planet Duckworld is home to an advanced civilization of anthropomorphic ducks, including a city-dweller named Howard T. Duck. One evening, Howard’s apartment is pierced by an interstellar laser beam and he is propelled through the universe to Earth. Landing in Cleveland, Ohio, Howard finds himself outside a nightclub and suffers a series of attacks from inhospitable humans. However, he uses “quack-fu” martial arts skills to defend a young rock ‘n’ roll singer named Beverly Switzler, who is cornered by two aggressive admirers. Beverly is initially startled by Howard’s strange appearance, but she is enamored by his courage and invites him to her apartment. There, Howard explains that he recently abandoned his dream of becoming a musician and Beverly realizes they share similar ambitions. When Beverly suggests that Howard’s journey to Earth may have an unexpected and favorable outcome, since he has the chance to reinvent himself, Howard argues he is an outcast on Earth, and longs to return home. The next day, Beverly conceals Howard in a trash bag and escorts him to an appointment with her eccentric friend Phil Blumburtt, who works at the Natural History Museum. Phil, who aspires to be a world-famous scientist, delights in the opportunity to exploit Howard and is eager to uncover the mystery of his arrival on Earth, but Beverly and Howard are not impressed by Phil’s baseless theories, and are discouraged to learn he is a lowly janitor. Outraged by the ruse, Howard loses hope of finding a way home and ends his friendship with Beverly. He briefly finds work at a sex club spa, but is fired for being obstinate and returns to the street, where he is ridiculed by unfriendly gawkers, and coveted by duck hunters. With nowhere to go, Howard returns to the nightclub where he met Beverly and watches her perform with her band, Cherry Bomb. When Beverly’s manager, “Ginger,” plans to withhold her pay as blackmail for sex, Howard fights him with “quack-fu” and retrieves Beverly’s earnings. Backstage, Howard is annoyed by Phil Blumburtt’s new pseudo-scientific discoveries and protests when the boy plucks one of his feathers for a research sample. Beverly takes Howard to her apartment, asks him to be her new manager, and propositions him for sex, but he worries about comingling with a human and shuns her advances. As Beverly kisses Howard’s beak, Phil arrives unannounced with two colleagues, a young man named Carter and his boss, Dr. Walter Jenning, who explains that he was testing a “laser spectroscope” the night Howard came to Earth. During a routine procedure, a mysterious force redirected the laser toward Duckworld, and Howard was accidentally extracted in the beam. Dr. Jenning proves his claim by procuring a feather that materialized in his laboratory the night of the transmission. He declares that the specimen is a genetic match with Howard’s sample feather, and adds that the nightclub where Howard “landed” is only a few miles away from the laboratory. When Howard suggests they reverse the laser to return him to Duckworld, Dr. Jenning warns they must perform the operation right away and goes back to the laboratory to prepare. Sometime later, Howard and Beverly arrive at the facility to discover the laser was already reactivated, and Dr. Jenning disappeared in the ensuing explosion. Chaos abounds, and police officers try to arrest Howard, but Beverly helps him escape. Reuniting with a disoriented Dr. Jenning, the friends speed away from the compound and police give chase. However, they break away from the pursuit and stop for a meal at “Joe Roma’s Cajun Sushi” diner. There, Dr. Jenning reveals that his laser spectroscope has been appropriated by a group of alien demons called the “Dark Overlords of the Universe.” Long ago, the evil creatures were sequestered in a region of outer space near Duckworld, but they saw a chance to escape on the night of Dr. Jenning’s experiment. Redirecting the laser toward their quarantine, the Dark Overlords hoped to transmit themselves to Earth and achieve world domination, but Howard unwittingly intercepted the beam. When the demons made a second attempt earlier that day, Dr. Jenning became possessed by one of the Dark Overlords. Speaking with the demon’s voice, Dr. Jenning declares he is on a mission to beam the remaining overlords to Earth, and Beverly’s body will host their evil spirits. Despite the severity of Dr. Jenning’s message, Howard and Beverly disregard his tale and believe he is still shaky from the explosion. However, the doctor becomes increasingly agitated, and his body begins to transform into a radioactive zombie. Meanwhile, diner patrons take an immediate disliking to Howard and deem him a threat to the community. As they attack Howard and steal Dr. Jenning’s laser spectroscope “code key,” Beverly startles the angry mob by declaring that Howard is her boyfriend. Dr. Jenning emits laser beams from his body to retrieve the key and abducts Beverly in a stolen truck. Although Howard escapes, he is helpless to save Beverly until he reunites with Phil, who arrives at the diner in the back of police car. The two flee on an electric glider aircraft and return to the laboratory, where Beverly is restrained under the laser spectroscope. Dr. Jenning, who is still possessed by the Dark Overlord, inserts his key into the device and programs it to transmit the remaining demons to Earth, but Howard interrupts the procedure by shooting him with a newfangled “neutron disintegrator gun.” As Dr. Jenning regains consciousness, he reports that the demon has been exorcised from his body and the friends celebrate their victory. However, an enormous, tentacled monster rises from the laboratory floor and activates the laser once and for all, giving Howard four minutes to save mankind from the remaining Dark Overlords. When the creature paralyzes Beverly and Phil in a static laser beam, Howard comes to their rescue and blasts the monster with the neutron disintegrator. Still, the laser spectroscope remains activated, and the surviving Dark Overlords will be beamed to Earth in just a few seconds. Beverly warns Howard that he will not be able to return home if he destroys the spectroscope, but he pulverizes the apparatus and rescues humanity from evil oppression. Howard adjusts to his new life and Beverly’s band thrives under his management. At a sold-out concert, Howard finally fulfills his dream of becoming a musician by joining Beverly onstage for a guitar solo, and he is cheered by an adoring crowd.