Based on the Pulitzer Prize-winning play of the same name by Mary Chase about gentle but eccentric Elwood P. Dowd's friendship with a white rabbit who is over six feet tall and invisible. Elwood's sister Veta, concerned with finding the right husband for her daughter Mertyle Mae, is frustrated by Elwood's behavior regarding Harvey. Veta's lawyer Judge Gaffney advises her to commit Elwood to Chumley's Rest, an asylum run by Dr. Chumley. But things go awry when Dr. Chumley, Dr. Sanderson, their assistant Kelly and the asylum "rule enforcer" Wilson try to commit Veta instead of Elwood.