Frances Armitage, a British widow with grown children and a patronizing daughter-in-law, is amazed when she lands the first job she applies for--as chaperone to U.S. movie star Twinkle, age 14 but passing for ten, about to make a film in England. Twinkle is the quintessential kiddie star: talented and tyrannical, driven to malicious behavior by the need to conceal her maturity and by the affair between her shallow mother and Dick Brouder, the movie's director. And, as filming proceeds, Frances senses that someone's out to get Twinkle--a script girl (known only as ""Continuity"") is poisoned, scriptwriter Morris Moskva has a fatal ""accident."" Tracing the culprit requires no detection, however, and suspense takes second place to the interplay of personalities here--it's a fairy tale in old-Hollywood style, with villains who aren't really all that nasty and happy endings all around. A charmer, then, but unlike Babson's sturdy The Lord Mayor of Death (p. 823), not for fans of the nitty-gritty.