In the X-Files office at Bureau headquarters in Washington, D.C., Agt. Mulder informed Agt. Scully of the arrest the previous night of Dr. Jason Nichols, Associate Professor of Biology at the Massachusetts Institute of Technology (MIT). Dr. Nichols was suspected of murdering his academic advisee, Dr. Lucas Menand. Dr. Menand had died when struck by a bus on the MIT campus in Cambridge, Massachusetts. Drs. Nichols and Dr. Menand had earlier been observed arguing; the bus driver stated that Dr. Nichols had pushed Dr. Menand into the bus’s path. Agt. Mulder played for Agt. Scully a video tape of Dr. Nichols’s statement to police.
In that statement, Dr. Nichols claimed to have been attempting to save Dr. Menand from being struck by the bus. Dr. Nichols also stated that shortly before the bus’s arrival, Drs. Menand and Nichols had been urgently warned by an unidentified elderly man that the bus would kill Dr. Menand. According to Dr. Nichols, the elderly man had called Dr. Nichols by his first name and had accurately predicted the exact time, place, and means of Dr. Menand’s death. The elderly man’s warning had then been interrupted by the arrival of a campus security officer, who then drove the elderly man away in his car. Drs. Menand and Nichols had parted. The bus had then arrived. Dr. Nichols claimed to have observed Dr. Menand standing in the street and to have sprinted toward Dr. Menand, but to have arrived too late to prevent Dr. Menand from being struck by the bus. Agt. Mulder informed Agt. Scully that the campus security officer who had arrested the elderly man had later been found dead.
Agts. Mulder and Scully immediately traveled to the office of Medical Examiner of Boston, Massachusetts. There they interviewed the coroner, who showed them the body of the campus security guard. The guard appeared to be frozen in a state of hypothermia of medically unprecedented extremity. The coroner stated that the body’s temperature was 15 degrees Fahrenheit when it was discovered in the car. Although the guard had a history of alcoholism, and might therefore have been assumed to have fallen asleep and frozen to death, the low temperature of the night of the night before had been only 28 degrees Fahrenheit. Agt. Scully measured the body’s temperature and observed that the body had grown even colder. She suggested the cause of death as exposure to a chemical refrigerant.
At the 6th Precinct, Agt. Mulder interviewed Dr. Nichols. Dr. Nichols stated that Dr. Menand had threatened Dr. Nichols’s reputation by claiming that Dr. Nichols had falsified data in his research. To Agt. Mulder, Dr. Nichols denied having falsified his data. He added that he and Dr. Menand had been in competition for the same research grant. When Agt. Mulder described the condition of the guard’s body, Dr. Nichols revealed that his research was in the field of cryobiology. Agt. Scully then called Agt. Mulder and informed him that Dr. Nichols’s thumbprint had been found on the guard’s uniform and in the guard’s car.
Meanwhile, at the Hotel James Monroe, a Japanese man identified as Dr. Yonechi attempted to check in. The elderly man whom Drs. Nichols and Dr. Menand had encountered the night before met Dr. Yonechi at the desk. Dr. Yonechi did not know the elderly man. The elderly man explained that he had reserved a room for Dr. Yonechi and had come in the place of Dr. Nichols, whom Dr. Yonechi had expected to meet. The elderly man also described himself as a great admirer of Dr. Yonechi’s work. In room 312 of the hotel, the elderly man expressed his personal gratitude for Dr. Yonechi’s solution to the problem of vitrification. Dr. Yonechi, appearing confused, stated that vitrification had not yet been solved. The elderly man described the solution, which he attributed to Dr. Yonechi. He called Dr. Yonechi by a nickname. Dr. Yonechi appeared to be impressed by the solution the elderly man had proposed. The elderly man then pricked Dr. Yonechi with a metal stylus and apologized to Dr. Yonechi. Dr. Yonechi immediately exhibited signs of rapidly advancing hypothermia. He quickly died.
Later that night, at the hotel room, Agts. Mulder and Scully examined Dr. Yonechi’s body. It had frozen in a manner similar to that of the campus security guard. Agt. Scully discovered a prick mark on Dr. Yonechi’s hand. Agt. Scully suggested that the elderly man was Dr. Nichols’s accomplice in using cryobiological knowledge to eliminate his scientific competition. She then showed Agt. Mulder a printout of an analysis of blood taken from the bodies of Dr. Yonechi and the guard. Both samples contained the same unidentifiable chemical compound.
At the Bio-Medical Research Facility of MIT, Agts. Mulder and Scully interviewed Dr. Lisa Ianelli, Dr. Nichols’s girlfriend. Agt. Scully showed Dr. Ianelli the blood analysis. Dr. Ianelli recognized the compound as a catalyst for an endothermic reaction that caused rapid freezing. She described the catalyst as Dr. Nichols’s theoretical work and stated that the technology necessary to synthesize the catalyst was years in the future. The agents informed Dr. Ianelli that the compound had been discovered in the blood of frozen bodies. Dr. Ianelli suggested that Dr. Yonechi might be susceptible to resuscitation.
In the frostbite bay of the Facility’s cryobiology lab, Dr. Ianelli and a doctor warmed Dr. Yonechi’s body in a tub and then attempted to resuscitate him, using drugs and electrical heart defibrillation. Agt. Scully expressed skepticism that the resuscitation of a body with a temperature of 8° F could be effective. Dr. Yonechi’s heart then began to beat. His temperature rapidly rose well past normal. He underwent grand mal seizures and then burst into flame. After firemen had extinguished the blaze, Agt. Scully and Dr. Ianelli discussed the results. Dr. Ianelli suggested that the freezing catalyst had been unstable. She speculated that had she left Dr. Yonechi in the warming tub, she might have saved him. Agt. Mulder reminded her that the catalyst did not yet exist. Dr. Ianelli left, announcing her intention to speak to Dr. Nichols.
On a city bus, Dr. Ianelli noted that she was being followed by the elderly man. She entered an academic library and confronted the elderly man. Dr. Ianelli accused the elderly man of killing Drs. Menand and Yonechi. The elderly man informed Dr. Ianelli that he had come to kill her. He showed her the metal stylus. He said he knew that she was being protected by Dr. Nichols. He then refrained from attacking her and fled. Dr. Ianelli called Agts. Mulder and Scully and met with them on a public bench. She described the confrontation. Shown a police sketch, she identified her follower as the elderly man. She confessed to having falsified data in Dr. Nichols’s research in an effort to win grant money and stated that Dr. Nichols was taking the blame to protect her. Police then arrived and informed the agents that the elderly man had been witnessed at the Lighthouse Hotel on McKinney Street.
Agts. Mulder and Scully proceeded to the Lighthouse Hotel and used a pass key to enter the elderly man’s room. They discovered a note of Dr. Yonechi’s flight information and a photograph of Drs. Yonechi, Nichols, and Ianelli celebrating in a laboratory. Agt. Mulder stated his belief that the photograph had not yet been taken. He explained his theory that the elderly man was Dr. Nichols, returned to the present from the future. He further suggested that the elderly man was attempting to ensure that the future would never occur. He pointed out that if Dr. Menand had been saved from the bus accident, Dr. Nichols would have been discredited, and that if Dr. Yonechi had died, the collaboration depicted in the photograph would not have occurred. Agt. Mulder quoted Agt. Scully’s senior thesis in support of the possibility of time travel. He suggested the agents show Dr. Ianelli the photograph and ask her if she remembered the photograph ever having been taken.
After the agents left the room, the elderly man returned there. He appeared ill and exhausted. He pricked his arm with the metal stylus and appeared to feel relief. Dr. Ianelli then entered the room. Having recognized the elderly man as Dr. Nichols from the police sketch, she addressed him as Jason. The elderly man told Dr. Ianelli that she had made time travel possible. He predicted that in ten years she would have a scientific revelation that would connect his cryobiological research to new discoveries in subatomic physics and allow time travel. He implied that such time travel would require conditions of extreme cold. Dr. Ianelli touched the elderly man and observed that he felt cold. The elderly man then pricked her with the stylus. Dr. Ianelli rapidly entered a state of advanced hypothermia and froze.
Upon learning that Dr. Ianelli had also frozen, Agt. Mulder arranged bail for Dr. Nichols and proceeded to the precinct, where he informed Dr. Nichols of Dr. Ianelli’s condition. In his car, Agt. Mulder explained to Dr. Nichols his theory that the elderly man was Dr. Nichols at a later age. He showed Dr. Nichols the photograph taken from the elderly man’s room. Agt. Mulder went on to explain his belief that the elderly man’s motive in returning to the present was to prevent a time-travel application of Dr. Nichols’s cryobiological research. Dr. Nichols stated that if Agt. Mulder were correct, Lisa’s freezing was Dr. Nichols’s fault. Agt. Mulder and Dr. Nichols then proceeded to the Bio-Medical Research Facility of MIT.
In the frostbite bay at the Facility, Agt. Scully was meanwhile assisting a doctor’s attempt to resuscitate Dr. Ianelli, following procedures Dr. Ianelli had used in her attempt to resuscitate Dr. Yonechi. Dr. Ianelli’s heartbeat was restored. Her temperature began to rise rapidly. Agt. Scully ordered the doctor to return Dr. Ianelli to the tub. Agt. Mulder and Dr. Nichols meanwhile entered the Facility, where they were informed by a security guard that the computer listed Dr. Nichols as already being in the building. Agt. Mulder sent Dr. Nichols to summon Agt. Scully from the frostbite bay. Agt. Mulder then proceeded to the cryogenics laboratory. There he encountered Dr. Nichols’s research assistant. While the assistant accessed Dr. Nichols’s computer files for Agt. Mulder, Agt. Mulder received a call from Agt. Scully, who informed him that Dr. Ianelli’s temperature had been stabilized. She reported that Dr. Nichols had not arrived at the bay. The research assistant then informed Agt. Mulder that Dr. Nichols’s disk drive had been erased from the mainframe computer. Agt. Mulder hastened to the Facility’s mainframe computer room.
Before Agt. Mulder arrived at the mainframe room, Dr. Nichols confronted the elderly man there. The elderly man begged to be allowed to finish his destruction of Dr. Nichols’s work. Dr. Nichols begged the elderly man to show him how to travel back in time to prevent Dr. Ianelli’s freezing. The elderly man refused, informing Dr. Nichols that he and Dr. Ianelli had created a world without history or hope, in which all things are known. Dr. Nichols physically attacked the elderly man, demanding to know the secret of time travel. Agt. Mulder arrived at the scene and shouted through a glass wall that Dr. Ianelli was alive. The elderly man held Dr. Nichols and the two men appeared to begin burning. Agt. Mulder broke a hole in the glass wall with a fire extinguisher. The elderly man and Dr. Nichols burst into flame. Dr. Nichols was burned to death. The elderly man’s body was not found.
Escorting Dr. Ianelli from the frostbite bay to an ambulance, Agt. Scully assured Dr. Ianelli that the theory regarding the instability of the catalyst had been proved by Dr. Ianelli herself when her temperature had been stabilized by returning her to the tub. Dr. Ianelli insisted that the elderly man was Nichols. Agt. Scully informed Dr. Ianelli that Dr. Nichols had died in a fire in the mainframe building. Dr. Ianelli was then transported to a hospital.
Agts. Mulder and Scully then discussed the absence of the elderly man’s corpse. Agt. Scully suggested that the agents issue an all-points bulletin. Agt. Mulder stated his belief that the elderly man would never be found. When Agt. Scully pointed out that Agt. Mulder’s theory could never be proved, Agt. Mulder, again quoting Agt. Scully’s thesis, suggested that the future could not be altered and that both the chemical catalyst and time travel would one day be discovered.
Dr. Ianelli later reconstructed the chemical catalyst and continued her research.