A BBC Radio full-cast dramatization starring John Moffatt as the great Belgian detective. Alice Ascher is murdered at Andover. Betty Barnard is strangled at Bexhill-on-Sea. Each time, an ABC railway guide is found by the dead bodies and, each time, Poirot is warned in advance by a letter from someone signed "ABC." But who is ABC? And can Poirot find out in time to prevent the death of C?