The Prologue (Magnolia) Magnolia
The first six minutes of Magnolia have nothing to do with any of the film's nine storylines. A narrator (Ricky Jay) recounts three stories of extraordinary coincidence, each resulting in death. The prologue establishes the film's governing principle -- that improbable connections are the normal texture of life -- before a single character appears.
Three stories establish coincidence as ordinary
The Greenberry Hill hanging (1911). Three men -- Joseph Green, Stanley Berry, and Daniel Hill -- are hanged for the murder of Sir Edmund William Godfrey on Greenberry Hill, London. The coincidence: Green-Berry-Hill murdered a man on Greenberry Hill.
The scuba diver (1983). Delmer Darion, a blackjack dealer at the Peppermill Hotel and Casino in Reno, Nevada, is scooped out of a lake by a firefighting plane and deposited on a forest fire. He dies of a heart attack "somewhere between the lake and the tree."
The Barringer suicide. Seventeen-year-old Sydney Barringer jumps from a ninth-floor rooftop. His parents are arguing three stories below -- his mother has a shotgun aimed at his father. The gun fires as Sydney passes the window; the blast kills him. A safety net installed three days earlier for window washers would have saved his fall. His death is ruled a homicide: he had loaded the gun himself weeks earlier, knowing his mother always threatened his father with it. (wikipedia)
The narrator insists on the significance of these events: "This was not just a matter of chance. These strange things happen all the time."
Anderson shot the 1911 sequence with a hand-cranked Pathe camera
The prologue's visual style shifts to match each story's era. The 1911 hanging sequence was shot with a hand-cranked Pathe camera authentic to that period, giving it a texture distinct from the rest of the film. The 1983 sequence is shot in a more conventional register. The Barringer story -- the most elaborate -- is staged as a miniature thriller. The visual variety establishes from the first frame that Magnolia will operate across multiple registers. (wikipedia, mentalfloss)
Ricky Jay's narration sets the film's tone of detached wonder
Jay -- a character actor and noted illusionist -- delivers the narration with a tone of scholarly bemusement. He is not amazed by these coincidences; he is pointing them out as evidence for a thesis. His voice gives the prologue the quality of a documentary lecture, which contrasts with the raw emotional intensity that follows.
Jay also plays Burt Ramsey, the What Do Kids Know? producer, within the main narrative. His dual role -- narrating the frame story and participating in the main story -- blurs the line between observer and participant, a theme the film returns to repeatedly. (wikipedia)
The prologue prepares the audience for the frog rain
The three coincidence stories serve a structural function beyond theme-setting: they train the audience to accept improbable events as part of the film's reality. When frogs fall from the sky nearly three hours later, the prologue has already established a world where such things happen. Stanley Spector's calm reaction -- "This happens. This is something that happens" -- echoes the narrator's stance: in this universe, anomalous events are natural.
Roger Ebert recognized the prologue's function in his Great Movies essay: the film's opening "sets up the theme of the film, which shows people earnestly and single-mindedly immersed in their lives, hopes and values, as if their best-laid plans were not vulnerable to the chaotic interruptions of the universe." (rogerebert)
The narrator returns at the end
The narrator's voice closes the circle in the film's final minutes, returning over a montage of the frog rain's aftermath. He circles back through the prologue's stories of coincidence: "Strange things happen all the time." The recurring line "We may be through with the past, but the past ain't through with us" -- attributed to multiple sources but used as the film's governing motto -- accompanies the transition from cosmic catastrophe to Claudia's intimate smile.