What are you lookin at?
~ Jack Shepard.

Jack Shepard is the main antagonist of the 2000 sci-fi thriller film "Frequency"

He was played by actor Shawn Doyle.


In New York City during October 1999, John Sullivan (Caviezel), a 36-year-old homicide detective, is still traumatized over the death of his fireman father Frank (Quaid). Living in the same house where he grew up, he discovers his father's ham radio following a breakup with his girlfriend Samantha (Melissa Errico) and begins transmitting. Because of unusual aurora borealis activity, John discovers he has managed to make contact with his father exactly 30 years in the past the day before his death in a warehouse fire. Though Frank doesn't believe it is John, John is able to shout out a warning about the fire that took Frank's life. The next day as he tries to escape a burning building Frank remembers John's words and escapes safely.

By saving his father from the fire, John has created a new timeline while retaining his memory of the old. At midnight, he tries calling his mother, but instead gets an answer from a deli. Later that day, John tries to patch up his relationship with Sam, but she does not remember him. John later discovers that in this new timeline Frank had died of lung cancer, and John's mother Julia Sullivan (Elizabeth Mitchell) was murdered by a serial killer. John is able to piece together that his mother's killer was called the "Nightingale Killer," a man who originally murdered three nurses before he vanished, but with the past changed he has now murdered 10, with Julia as the sixth. Using information from 1999 police files on the impending six killings, John and Frank work together across the gap of time to stop the murderer in 1969 and save Julia and the other six nurses. Frank successfully averts the murder of the first expected victim, but when he tries to prevent the next, he is attacked by the killer in a nightclub bathroom and his driver's license is taken from his wallet. When he regains consciousness, Frank rushes to the woman's apartment only to find he is too late.

John realizes the killer's fingerprints are now on Frank's wallet and Frank is able to bag the wallet and hide it under a floorboard in the house, allowing John to retrieve it in 1999 and take it in to his crime lab. John learns that the fingerprints belong to a now-retired detective named Jack Shepard (Shawn Doyle). It's shown that the reason he now has more victims was because Julia left the hospital in the original timeline and wasn't there to save his life from a medical mistake. In this new timeline he presumably stopped after being caught up in the Knapp hearings. Meanwhile in 1969, Frank is arrested by Satch DeLeon (Andre Braugher), his friend and John's future partner, when police find Frank's driver's license with Jack Shepard's latest victim. As Frank struggles to continue speaking to John as Satch struggles with him, the ham radio is knocked off of Frank's desk and broken. At the station, Frank, using improvised skills from his veteran firefighting knowledge, is able to escape and searches Jack's apartment for evidence. Meanwhile Satch, having been told by Frank about his communications with his son, watches the 1969 World Series and realizes Frank has told the truth when events he described to him come true. Jack is presumed dead after a struggle with Frank and Frank is cleared of charges.

Frank returns home and repairs the radio, happily telling John that Shepard is dead and Julia is saved. However, John's photographs still include Julia's death. Suddenly, in both 1969 and 1999, Jack breaks into the Sullivan home. While father and son both fight Shepard, the past Shepard is distracted by Julia and Frank shoots off his hand with a shotgun, causing him to flee. In 1999, Jack is choking John when his hand shrivels and vanishes. The house ripples and the furnishings change as the timeline is adjusted, and Jack is shot and killed by an aged Frank, the new alterations to the timeline saving both him and Julia. The film concludes with a neighborhood baseball game in 1999. Frank and Julia are there, along with John, who is now married to the ex-girlfriend who left him in the original timeline. She is now pregnant and already has had one son with John. Also, due to some advice John gave him over the radio, his best friend Gordo's life is now better. As John wins the game with a home run that allows both himself and Frank to score, a montage is shown of John's life with his parents in the new timeline.