Frequency is a 2000 American science fiction thriller drama film directed by Gregory Hoblit and distributed by New Line Cinema. It was written by Toby Emmerich. Its story follows John Sullivan, a homicide detective in New York City who accidentally discovers a cross-time radio frequency on his late father's ham radio, which allows the two to speak to each other across time. It stars Dennis Quaid, Jim Caviezel, Shawn Doyle, and Elizabeth Mitchell.


In October 1969, FDNY firefighter Frank Sullivan (Quaid) dies in a warehouse fire, leaving behind his wife Julia, a nurse, and six-year-old son John. Thirty years later, in 1999, John, now an NYPD detective, is dumped by his girlfriend Samantha for being emotionally shut off. John's neighbor and childhood buddy, Gordo, finds a Heathkit single-sideband ham radio that once belonged to Frank, but fails to get it working. The night before the anniversary of his father's death, John is surprised to find the radio operating during an occurrence of the aurora borealis, and has a brief conversation with another man concerning the 1969 World Series, which John is able to recount in specific detail. Eventually, he realizes that the other man is his father in 1969 and tries to warn him of his impending death. The next day, while attempting to rescue a young girl, Frank remembers John's warning and manages to escape the burning warehouse. In 1999, everyone is given an altered set of memories brought about by Frank's survival, but only John simultaneously remembers his father dying in the fire. That evening, Frank and John reconnect and learn a great deal about each other's lives.