At the Japanese Consulate in Honolulu, officials are burning papers throughout the building. Doug and Tony land in a corner and the Japanese consulate members stare in shock. The scientists try to explain that they're just tourists who entered by accident. The consul, Tasaka, doesn't believe them.
At Project Tic-Toc, the team watches and notices the date on the desk calendar: December 6, 1941. Kirk realizes that it's the day before the bombing of Pearl Harbor. They try to get a time lock while Tasaka orders the scientists out. The consul explains to his people that Doug and Tony must be spies but if they killed them, then their superiors would trace them to the consulate. He sends his man Sumida to follow them and kill them if they do anything suspicious.
Outside, Doug and Tony also noticed the desk calendar and realize that the consulate members were burning their secret codes in anticipation of the attack. Tony explains that his father used to drive him to Pearl Harbor and informs Doug that he was seven years old and living in Honolulu at the time of the attack with his father, Lt. Commander Tony Newman. Newman was reported missing after the attack and never found. Tony suggests that they go to see to his father and find out what happen, and possibly warn him. The young scientist remembers spending the day with his best friend, Billy Neal, and Newman joined them for dinner.
The two scientists go to the Neal home with Sumida following them from a distance. Doug knocks at the door and the family servant, Yuko, ushers them in when Tony says he has important business there. As they wait for Louise Neal, Billy's mother, Tony looks around the home and describes his father, who will be the same age that he is now. He tells Doug that the house was destroyed during the attack the next morning. Louise comes in and tells them that Newman is running late because he stopped to pick up Admiral Brandt. She wonders if they are there because of her husband and explains that he's aboard the Enterprise
and isn't expected until 8 the next morning.
Sumida comes to the back door and Yuko, well aware of who he is, ushers him in so he can watch the Americans. She warns Sumida that the butler, Ichiro, has American sympathies. When the butler comes in, Sumida stabs him and hides the body.
Newman arrives and tells Louise that Brandt will be along shortly. He finds Tony vaguely familiar-looking and Tony says that they met a long time ago. He then tells his father that his life will be in danger the next morning when he goes to the base. Newman is puzzled but Tony refuses to explain further. The officer demands the truth and Tony tells him that Japan is planning a massive air attack. In the dining room, Sumida and Yuko secretly listen and realize that someone knows about their plans.
The officer insists that the Japanese fleet couldn't approach Hawaii without their knowledge but Tony describes how Japan is sending two-third of their fleet there while the other third make a feint toward Indochina. When Newman wonders what their source is, Tony tells his father how he studied mathematics in college and knows about the possibility of time travel. The officer dismisses them as dangerous lunatics but before he can pursue the matter, Billy and Young Tony run in and ask to stay up late. Louise comes in after them and orders them to bed, and Doug warns Tony that the children will be there when the house is destroyed. Tony starts to tell his father who he really is, but Yuko interrupts to tell them that Ichiro went home because his wife is sick. Newman tells Tony and Doug to ship out to the states if they're nervous about an attack and has Yuko escort them out.
As Yuko escorts the two scientists out through the dining room, Sumida draws a gun on them and orders them out. At the base, the team loses their lock on their friends and catches a glimpse of the Japanese fleet heading for Hawaii.
Tasaka drives to an import warehouse where Sumida is holding Doug and Tony. The scientists have told Sumida the truth but he doesn't believe them. Tasaka doesn't believe them either and offers to release them in the morning if they tell him the truth. Doug maintains h is story and Tasaka has his assistant Okuno administer sodium pentothal to him.
Admiral Brandt arrives at the Neal home and tells Newman that the Japanese fleet was sighted off the coast if Indochina. Newman remembers that Tony told him the same thing but Brandt dismisses it as a lucky guess. Brandt says that he gets a dozen predictions about attacks on Pearl Harbor per day. When Louise comes in, Newman says that he has to check on something at the base and offers his apologizes.
Under the influence of the truth serum, Doug maintains his story and describes the Japanese attack plan after Pearl Harbor. Tasaka starts to believe him until Doug informs him that the Japanese will lose after Hiroshima. They prepare to administer truth serum to Tony, who says that he will say the same thing and angrily asks if they want to hear about the atomic bomb.
Newman drives to the naval communications office and confirms the report about the Japanese fleet. He has Lt. Tom Anderson call Washington and authenticate the report.
Under the influence of the drug, Tony says that they entered the office via the Time Tunnel. Tasaka is interested to hear that the scientists work with the U.S. government and assumes that they're spies. However, he Tony's claim that they're trying to help his father as meaningless babble and figures that they've been brainwashed to believe the story. Tasaka confirms that they told Newman about the attack but Sumida reports that the commander didn't believe them. The consul tells his assistant to dispose of Newman to be sure and goes to make a report to Tokyo while Sumida guards the scientists.
Louise receives a call from Ichiro's wife asking what happened to her husband. Once she hangs up, Louise goes to the dining room and finds a few drops of blood on the carpet. Okuno comes in and demands to know where Newman is. He assumes that the commander is still there and goes to check out the boys' room. Louise draws a gun on him and Okuno runs off, and she calls Newman at the naval base. Newman tells her that he'll send a marine guard, and she goes in to make sure the boys are okay. Relieved, she breaks into tears.
At Project Tic-Toc, the team continues to watch the Japanese fleet as they launch their planes for the attack. Swain intensifies the probe in an attempt to get a lock on Tony. They end up focussing on Young Tony briefly and then get a lock on Tony and Doug. The fix is still drifting and Kirk realizes that if Young Tony dies in the bombing, their Tony will cease to exist whether they pull him out with Doug or not.
Tony and Doug watch the clock and realize they only have an hour and fifteen minutes until the bombing. Tasaka calls and Sumida steps out of the room to answer it. Once they're alone, Tony and Doug slide around back-to-back and free themselves. Meanwhile, Tasaka gets orders from Tokyo to kill the two scientists. When Sumida goes back with two of his men, Doug and Tony jump them and get away.
Louise calls the base and asks for Newman. Anderson takes the call and says that Newman has stepped out, and Louise asks him to tell the commander that everything is all right and she sent the marine guard back. As she hangs up, Newman returns and Anderson tells him about the call. He's confirmed the report that the Japanese fleet is near Indochina and goes off to get breakfast.
At the base, Jerry insists that they have to do something and the others say that it's already happened and that it can't be changed.
Tony and Doug go to the Neal home and warn Louise that the house is in the target area and will be destroyed in 30 minutes. They tell her to head into the mountains and Louise assumes that Newman sent them. When Louise hesitates, Doug and Tony tell her that Yuko is a spy and that she didn't show up for work that morning because she knew about the attack. Louise agrees to take the children to the mountains, and Billy comes in and tells them that Tony is gone. The scientists tell her to get to the mountains with Billy and try to work out where Young Tony might have gone. Tony tries to remember where he went that morning but realizes that the shock of the bombing wiped out his memories. Doug figures that Young Tony heard them talking about the bombing and ran to the base to warn his father.
Tony catches up to Young Tony and tells him that he wants Newman to live as much as the boy does. He asks his younger self to go back to Louise and leave with the Neals while he warns the commander. As Doug arrives, Tony tells his friend to get Young Tony back to the Neal house and then runs to the base.
As Doug gets Young Tony and the Neals out of the house, the Japanese begin their attack. Once they're clear, Doug sends the others on ahead and says that there's something he has to do.
At the base, Anderson heads for the Japanese consulate while Newman supervises the base. Tony runs into Anderson and gets directions, but debris hits him and knocks him unconscious.
At the consulate, Tasaka, Sumida, and Okuno prepare to evacuate. Anderson and two military policemen pull up as Doug arrives and tells Anderson that the Japanese are inside. They capture Tasaka and his men and Doug drives the consulate's car to the base to find Tony.
At Project Tic-Toc, the scientists watch as Tony recovers consciousness. Doug pulls up and picks up his friend, and they head for the base.
As Newman tries to contact the Enterprise
and warn them away, a bomb hits the communications center. The injured commander confirms that the radio is destroyed before passing out. Nearby, a bomb has landed without detonating but is still ticking. Kirk and the others, watching, realize that it could go off in a few seconds. Jerry tries to relocate the bomb in another time zone but Swain and Anne stop him, warning that innocents could be killed. The bomb disappears on the monitors... and reappears in the time tunnel. Jerry goes to disarm it while Swain warns that they have only 90 seconds before it returns automatically. Kirk evacuates the control center and seals it off, and then goes to help Jerry while Swain and Anne try to hold the bomb as long as they can. The two men work on the bomb and move off, and it disappears. Jerry warns the others that he's not sure if he disarmed the bomb in time.
Doug and Tony reach the command center and finding the dying Commander Newman. Doug repairs the radio and Newman insists on sending the signal to the Enterprise
himself. They confirm the order to turn back and Newman turns to Tony. He repeats what Tony said about knowing him earlier, and Tony says that his name is Tony Newman. Realizing who Tony is, Newman says that it's good to know that his boy will survive and then dies. Crying, Tony stays with his father a moment longer and then leaves with Doug.
As the two scientists get clear, the bomb finally detonates, destroying the communications center. Tony realizes that's why his father was never found. Another bomb strikes nearby and Kirk and the others realize that they have to attempt a time transfer. The signal drifts momentarily to Tony but then the team makes contact and transfers their friends out just in time.
Tony lands alone in a forest and calls to Doug. Two redcoats run by and hear something in the woods. They open fire while Tony runs off. He finds a campsite and steals some buckskins. Doug lands nearby and calls to Tony, who hears him. Someone opens fire as Tony joins his friend. After putting on the buckskins, Tony warns his friend that they're in the middle of a war zone and Doug concludes from the surroundings that they're somewhere in the southern U.S. The redcoats return and spot them, and Tony and Doug run toward the American lines. Doug trips and a soldier opens fire on him...