When Elwood P. Dowd starts to introduce his imaginary friend, Harvey, a pooka in the shape of a six-foot, one and a half-inch tall rabbit, to guests at a society party, his society obsessed sister, Veta, has seen as much of his eccentric behavior as she can tolerate. She decides to have him committed to a sanitarium to spare her daughter Myrtle Mae and their family from future embarrassment. When they arrive at the sanitarium, due to a comedy of errors, the doctors commit Veta instead of Elwood, but when the truth comes out, the search is on for Elwood and his invisible companion.
