Beatrice Umbo is a chimpanzee expert and enthusiast. When she decides to retire in her Connecticut hometown, she adopts Konrad, a chimpanzee who was raised as a human during an experiment in the 1960s. When Konrad is delivered to her home, he makes himself comfortable in her living room, rests his feet on her coffee table, and pulls out a cigar.

One day, when Beatrice is at the grocery store, she is recognized by one of her fans, Howie. Howie offers to help carry her bananas home. Unexpectedly, Howie and his father show up at Beatrice's house to ask her to sign a book. She invites them in, and they are introduced to the spectacle that is Konrad. He bounces around the house while yelling and stealing, but his craziness doesn't deter Howie and his father. In fact, they stay for a while, and Howie invites Beatrice on a ride in his Cessna airplane.

When he comes to pick her up for their flight, Beatrice asks to bring Konrad. Howie agrees. They circle around in the air, and Beatrice takes in the sights of the East Coast. However, before long, trouble strikes. Howie mistakenly thinks that Konrad had reached for the plane controls and grabs his wrists. Konrad freaks out and attacks Howie, which causes Howie to lose control of the plane.

Eventually, Konrad knocks Howie unconscious and bites off Howie's thumb. The plane, pilotless, continues flying over the Atlantic as Beatrice and Konrad gaze into each other's eyes.