A US/UK house-swap is the premise for this mediocre entry from prolific, erratic Babson--as the Harper family from New Hampshire moves, for the summer, into the London suburban home they've swapped with recently widowed Rosemary Blake. At first things seem jolly-all-right--if awfully foreign--for sharp-tongued Nancy, her professor-husband Arnold, and twins Donald and Donna. But eventually Arnold realizes that someone's trying (not very hard) to kill him. And his researcher's instinct sets him delving into the accidental death of Rosemary Blake's husband--who had curious relationships with the neighbors: Richard and Lania Sandgate; Lania's decorator-lover Piers Alperton; and relative newcomer Hazel Davies, who claims a husband and children that no one's ever seen. The puzzle's windup is a true copout--contrived, melodramatic, unbelievable--but there's some fun along the way, with shrewd observation and bright dialogue, as Nancy and family struggle to master the English life-style.