Story-wise,the trouble begins when American visitor Robert Mitchum, surely the most unlikely candidate for a sedate wander round s stately home in the film "THE GRASS IS GREENER," finds himself in Cary Grant's private quarters and, quite be chance, meets and falls in love with Deborah Kerr, the missus of the establishment and Grant's personable wife. How Grant sets about wooing his wife back, formed the substance of the plot, and involved the talents of Jean Simmons as an ex-girlfriend of Grant's, and Moray Watson as the butler. . . . Story-wise, the trouble begins when the suave Cary Grant, who plays an earl who, to supplement his income, has opened part of his stately home to the public. . . .and so on, and so on.