Hans Hagemann is the director of a prison in Berlin. He is about to take early retirement in order to join his future wife Nicole Carruthers on her boat in Sidney. Nicole is a champion yacht-racer and at the time on her way from Fiji to Australia. Also on board is Tina, Hagemann's daughter from his first wife, who died years ago. The trip is supposed to help them overcome a slight animosity in between them.
The film starts on Hagemann's last day in his old position, the 31st of December 1999. He makes a last round with a trusted old warden. The prisoners have somehow managed to find an interview with Nicole on TV and show it, while Hagemann goes around. There first is a party with the prisoners, later Laura Heine, the minister of justice arrives, for a more formal farewell-party. During her speech, one of the prisoners, Thomas Rasch, interrupts her. Rasch is a computer-programmer, who has been sentenced for killing his boss, the head of the famous IT company CAC. Rasch says, that if he isn't released and gets 100 million euros, a computer virus will stop the most important computer systems all over the world working, including all satellites.
At first they don't believe him, as he had only access to stand-alone computers during his time in prison. Things get a bit more worrying, when a TV broadcast from celebrations in Fiji is suddenly interrupted. Rasch declares, that this is a virus, he programmed before his sentence. He maintains, that he wrote the famous anti-year-2000-crisis software, that CAC has sold everywhere in the world. As he foresaw, that he might not get the credit for it, he built in the virus as his special kind of copyright. And also that he didn't kill the boss of CAC either. If his demands are not met, wherever this anti-crisis software is used, which is almost everywhere in the world, computers will stop at local midnight.
CAC are also having a party for the opening of their new office building in Berlin. Don Carpening, the new boss is expecting Laura Heine for the official opening. It turns out, that Laura Heine and Don Carpening have an affair and they look very much, as if they have some guilty secret too! Carpening is convinced, that his team can find the virus in time. They decide to have the crisis team inside the prison in order to be well protected. His and Laura's connection with each other is to be kept secret. They try to take over the prison, almost starting a revolt, but Hagemann persists in keeping the command, as he is still in office until midnight. The CAC team figures out, that if the virus is activated everywhere at midnight local time, it must await a signal from the observatory in Greenwich. As the official time-keepers for the whole world, they here and there have to insert an extra-second to adjust the calendar to the exact astronomical time. Such an extra-second is due at midnight of the 31st of december and the signal goes out from Greenwich to clocks in every time zone at their local midnight. Prof. Morley in Greenwich promises to help, as best as he can.
The CAC team find the virus just in time before the first millenium midnight in the pacific and the "antidote" is sent out from Greenwich. As we all suspected, the problem is not solved that easily: The TV transmission of millenium celebrations in Sidney is suddenly interrupted!
Hagemann can't reach Nicole anymore by mobile phone and Tina and Nicole on the boat start to suspect that their GPS satellite navigation system doesn't work anymore. Laura Heine calls the german chancellor to inform him about the situation. The chancellor refuses to meet Rasch's demands, as the government can't be blackmailed by a criminal. In Sidney, meanwhile, electricity breaks down and hospitals and airport are in great trouble. The CAC team resume their work on identifying the virus, while Hagemann tries to win Rasch's trust and make him defuse the virus himself. It turns out, that Rasch thinks that a millenium computer chaos would be good for mankind. The money he is asking would not be for himself, but for various organisations, mostly dealing with environmental problems. Hagemann's attempts are thwarted by the minister's body guards, who rush in and completely isolate Rasch from any further contacts.
Back on the boat, Tina and Nicole talk for the first time about Hans Hagemann. Tina tells about the time, when her mother died and her father was devastated. He completely withdrew into himself and went sailing on his own, whenever he had a holyday. On one of these trips, he met Nicole in Sidney. Hagemann is trying to find friends or colleagues of Rasch, who may be able to help, while TV broadcasting from Tokyo is cut off and there are news about lots of ships being in trouble in the pacific, because GPS systems don't work anymore. Hagemann tries in vain to call Nicole.
It turns out, that one of Rasch's friends, Maria Bauer, is actually on the CAC crisis team. As the team has come to a dead end anyway, Hagemann wants her to talk to rasch. The CAC experts have come to a place, where they need a password and they only have a limited number of tries! So what they now want, is the password from Rasch.
Hagemann and a few of his prison wardens remove the bodyguards in front of Rasch's cell and after several attempts, Rasch agrees to talk to Maria Bauer. She had a date with him on the night, that he was supposed to have killed his boss and heard them quarrel. Rasch later asked her to tell the police, that they were together but Maria refused to lie for him. After that, Rasch didn't talk to her anymore and even refused her visits in prison. In the end Rasch agrees to give the password, if his trial is reopened and his charities get the money. All the account number he has on a disk. He also says, that Laura Heine took bribes from CAC and Carpening to make the german government buy the anti-crisis software.
Meanwhile Nicole and Tina are stranded on a reef, the motor won't start and Tina has gone overboard. Next in line for midnight is Russia, where all the rocket systems have been fitted out with CAC software.
In this situation plus being confronted by Hagemann with her bribes, Laura Heine at last does her utmost to talk the chancellor into accepting Rasch's terms. Which he does, also considering the fact, that he himself pressured the Russians into getting the CAC software to make their rocket systems safer!
Meanwhile Carpening has knocked down Rasch's guards and tries to beat the password out of him. Hagemann and his colleagues can interfere, but Rasch has lost conciousness. During the general tumult, Carpening confesses to have killed the old CAC boss but claims, that he did it all out of love for Laura Heine. She denies all connections to Carpening.
Nicole and Tina have saved themselves on some rocky island, where a romantic sunrise takes place. At last they have become friends!
In Berlin midnight is getting nearer, the crowds celebrate without knowledge of the impending doom. Hagemann and Maria Bauer at last get through to Rasch, who tells them the password: Error 2000! Laura Heine now wants to withold the money but Hagemann insits, that it is transferred to the accounts of the charities on Rasch's disk.
The proper "antidote" is now broadcasted from Greenwich by Prof Morley. Berlin is saved and everywhere else, computers resume their work too, but Rasch dies on his way to hospital. Thank god, the mobile phone also works again and so does the GPS, which Nicole has wonderfully taken with her to the rocky island. So she can tell Hagemann her exact position, just before the batteries of the mobile phone give up. The Australian coastguard saves Nicole and Tina and later even find their drifting boat.
The film has a wonderful Happy End: Hans Hagemann awaits Nicole and Tina in the harbour of Sidney and they all sail off together!