The Mousetrap, the longest-running play in the English language, is 50 years old. This special edition comes complete with three other thrillers, showing how Agatha Christie’s olays are as compulsive as her novels, their colourful charcters and ingenious plots providing yet more evidence of her mastery of the detective thriller.Being cut off by snowdrifts is not an auspicious beginning, but Molly and Giles Ralston are determined to make a go of their new guest house. But among their first visitors is a maniac with an ambition to murder ‘Three Blind Mice’…