Who can introduce the story and reasoning content of dial m for murder in detail?

Tennis star Tom has been active on the court. He often goes abroad to take part in competitions, so he has to leave his beautiful young wife alone at home. Margo was born in a wealthy family in the upper class and has considerable wealth around her. She couldn't stand being alone at home for a long time, so she had an affair with her old classmate and writer Mark. When Tom is not at home, they often go out on dates. The relationship between the two developed very rapidly, and finally one day the trail was revealed. Tom dug out Mark's love letter from Margo's handbag, so he wrote an anonymous letter to his wife to remind her to exercise restraint. Unexpectedly, Mark came to haunt me again. It seems that only by designing to kill his wife can the doomed love be lifted. Tom's college classmate Lesgate is a man with a criminal record. Tom hired him to kill his wife with 1000. Lesgate is poor, but he dare not take risks easily. Under Tom's repeated threats and inducements, he finally agreed to get rid of his confidant Margo. Tom plans to invite Mark to a nightclub for a drink, and then hide the key to the living room under the carpet. At 0: 50 pm/kloc-0: 00, Lesgate entered the room on time, took out the key under the carpet, opened the door and entered the guest room, hiding behind the curtain. At about eleven o'clock, Tom will call home from outside, and Margo will come out of the bedroom to answer the phone when she hears it ring. According to Tom's careful design, Lesgate killed his wife when she answered the phone at her desk with her back to the window. Then put the key back under the carpet and walk out the door. The next night, the plan began to be implemented. Tom took out the key to the living room from his wife's handbag and hid it quietly under the carpet. After saying goodbye to his wife, he and Mark went straight to the nightclub. At about nine o'clock in the evening, my wife went back to the bedroom to sleep as usual. Next, Lesgate arrived on time at 10: 50, and everything went smoothly as planned. At about eleven o'clock, Tom didn't call, and Lesgate was in a hurry. He suspected that things had changed, so he was ready to leave. Just then, the telephone suddenly rang, and he was taken aback and quickly hid behind the curtain. Then when Tom's wife answered the phone, Lesguer tried to strangle her with a wire, but Lesguer didn't expect that Tom's wife was an actress and learned self-defense. When Lesguer met Tom's wife, Tom's wife was struggling, and there happened to be a pair of scissors on the telephone table. Kill Lesguer immediately. Tom thought there was no sound on the phone, and then he heard his wife's voice. His wife said, "I just killed a man!" " "Tom was shocked. His wife suspected that Tom wanted to hurt her, so she reported the case to the police, and then the police brought Tom to justice.