With her father off to WW I, 14-year-old Frances goes to stay with Aunt Bessie, housekeeper at Hallowes, a somber English estate. Lady Hallowes still mourns her son Simon, drowned at age eight; his twin, Martin, now 17, is both disagreeable and sinister. Frances is soon having encounters not only with the ghost of Simon, a nice chap who reports that Martin actually murdered him (since Simon was the elder) to get the inheritance, but with the ghost of Francesca, a gifted painter who died in childbirth at 18. Simon has been trying to catch Martin asleep so that he can take over his body. Frances tries to help (but fails; in retrospect, that might be awkwardly like murder); Simon succeeds, and there's the suggestion that when Frances is older they'll be even better friends. All of this is better-than-average gothic, smoothly told with pleasant shivers, but as predictable as the ""sinister and brooding"" landscape.