Seven years after his wife’s death, the eccentric John Dolittle (Robert Downey Jr.), famed doctor and veterinarian in Victorian England, becomes a hermit, hiding himself away behind the high walls of Dolittle Manor, with only his menagerie of animals for company. But when Queen Victoria (Jessie Buckley) falls gravely ill, a reluctant Dolittle is forced to set sail on an epic adventure to a mythical island in search of a cure, regaining his wit and courage as he crosses old adversaries and encounters wondrous creatures.