Attorney David Trask sets out on a cross-country plane trip to decide what to do about his marriage - his wife had been unfaithful and forgiveness wasn't on his mind. The trip had several layovers and a group of people, including Trask, became acquainted, in a seemingly superficial way and they exchanged contact information. The group included an alcoholic doctor, a failed actress and an obnoxious salesman.
The plane crashes and Trask is the only survivor. As he recovers, he comes across the contact information for those in their small group. Of course, their families already know of their deaths, but Trask contacts them to share and to listen - he was the last one to see them alive.
Phone Call from a Stranger has the potential to be overly sentimental, but it is cast and acted so well, that any sappiness to the script is quickly overlooked. Director Jean Negulesco may be most famous for being replaced after two months of work as the director of The Maltese Falcon by John Huston. He went on to make some very good films, including Phone Call from a Stranger.
Gary Merrill and Bette Davis were married by this time, but do not spend much time in the film together.