context: Ray and Polly Cutler (Showalter and Peters) on a delayed honeymoon at Niagara Falls, find their reserved cabin occupied by George and Rose Loomis (Cotten and Monroe). Rose tells them that George is asleep at last, and has recently been discharged from an Army mental hospital after his war service in Korea. The Cutlers politely accept another, less desirable cabin, and so the two couples become acquainted.
  
  
  
  
  Polly (Jean Peters) and George (Joseph Cotten)
  
  
  
  
  
  
  Rose (Marilyn Monroe)
  George and Rose have a troubled marriage. She is younger and very attractive. He is jealous, depressed and irritable. While touring the falls the following day, Polly sees Rose passionately kissing another man, Patrick, her lover. That evening the Cutlers witness George's rage. Rose joins an impromptu party and requests the playing of a particular record, at which George storms out of their cabin and breaks the record, because he suspects the song has a secret meaning for Rose. Seeing George has cut his hand with the record, Polly visits his room to apply bandages to his injury. George confides that he was a former sheep rancher whose luck turned for the worse after he fell in love and married Rose who he met when she was a barmaid.
  What George does not know is that Rose and Patrick are planning to murder him. The next day Rose lures George into following her to the dark tourist tunnel underneath the Falls. There Patrick is going to kill him. To let Rose know that George is dead, Patrick will request the Rainbow Tower Carillon play Rose's special song ("Kiss"; music by Lionel Newman, lyrics by Haven Gillespie, both uncredited). The tune is played on the carillon bells and Rose concludes George is murdered.
  In fact, it is George that has killed Patrick, thrown his body into the falls, and collected Patrick's shoes at the exit instead of his own. This leads the police to believe that George is the victim. The body is retrieved and the police bring Rose to identify George's body. When the cover is lifted from the face and she sees the body, she collapses and is admitted to hospital.
  The motel manager moves the Cutlers' belongings to the Loomis's cabin. George comes to the cabin to kill Rose in revenge, but finds Polly there instead. She wakes and sees him before he runs away. She tells the police, who launch a dragnet.
  During the Cutlers' second visit to the Falls, George finds Polly alone for a moment. Trying to escape, she slips and he saves her from falling over the edge into the waterfall torrent. He explains to her that he killed Patrick in self-defense and pleadingly says "Please ... let me stay dead." Polly leaves without answering. Later that day she tells the police detective that she believes George is alive. George has the carillon play "Kiss" again to panic Rose.
  She flees the hospital intending to return to the U.S.A. Finding George waiting at the border for her, she runs and tries to hide in the carillon bell tower. George catches her and strangles her beneath the bells, which remain silent. Remorsefully he says, "I loved you, Rose. You know that."
  The Cutlers go fishing with friends in a launch on a section of the Niagara River above the Falls. When the launch moors in Chippawa, Ontario for gasoline and other supplies, George steals the boat with Polly on board. The police are notified and set out in pursuit. The boat runs out of gas and drifts towards the Falls. As they near the edge, George scuttles the boat to slow it down and manages to get Polly onto a large rock before he goes over the Falls to his death. Polly is rescued from the rock by a United States Coast Guard Sikorsky H-19 Chickasaw helicopter.
question: How is polly rescued off the rock?
answer: by a United States Coast Guard Sikorsky H-19 Chickasaw helicopter.