Pop and rock music enthusiast Flemming, who is studying law, meets businessman Jan Irsinger. Together they begin to dream of breaking the national radio broadcasting monopoly, and provide young people with the swinging, rocking tunes they are hungry for. Along with Flemming’s girlfriend and fellow student, Gitte, they find a loophole that allows them to realise their dream if they can buy a ship and broadcast radio from international waters in the Øresund. Jan persuades his godfather, Preben Borg, to inject some money into the venture, and Flemming convinces his friend Richard, a bicycle repairman and avid amateur radio operator, to come on board as chief engineer.
In the newly purchased villa, which acts as a radio studio, things are getting hectic as the launch approaches. Jan and Preben hire poach new staff from the more established media. Advertising legends Schiøler Mortensen and Torben Stenbæk from Statsradiofonien join the team adding their high salaries to coffers that are already empty. Flemming has trouble balancing his radio work with his law studies. Jan tries to raise the funds they are lacking to launch the station successfully.
Christmas is just around the corner. Anne-Marie is working hard at the radio station, while her problems as a single mother are mounting. Jura Studios have now been downsized by Flemming, who must maintain a dangerous lie to ensure peace at Christmas. Peder Falk is still fighting to close Radio Mercur down, and sends in the tax man during their Christmas party, where Flemming discovers a hidden side of Jan.
Flemming has moved into the radio station’s basement after the row with his parents about dropping his degree course. A newspaper article on Denmark’s Most Eligible Bachelor puts Jan in the spotlight, and Lily pushes for grandchildren. Schiøler predicts a bonus to Anne-Marie, who immediately gives notice to Karen-Margrethe and Henry, and starts to look for a private apartment for her and Asger. However, It turns out that her announcement is premature.
1960 is upon us, and it is celebrated on the radio with a swinging New Year’s party. Anne-Marie has moved into her own apartment, Gitte has just returned from Paris, and advertising money is steadily flowing into Radio Mercur. However, Stenbæk feels constrained by Schiøler and the many advertisements that he has inserted into the channel. Peder Falk is planning further action to close Radio Mercur, and something is wrong with the new, expensive dress that Gitte brought home from Paris.
Six months have passed since New Year’s Eve, and Flemming and Anne-Marie have moved in together. Schiöler’s alcohol abuse is taking its toll on Anne-Marie, and with Flemming as radio’s most popular disc jockey, it is not easy to spend time together as a family. Jan has been sent to prison for ‘indecent assault’, and in his absence Stenbæk has gone on a controversial debate programme, which Preben tries to put a stop to in case it scares advertisers away.
Preparations are underway for a big radio show to open the new Mercury Theatre, but the internal conflicts are like a ticking time bomb and, with his usual optimism, Jan promises more than he can deliver in an attempt to rescue the rehearsal. Jan feels like Lily and Preben are freezing him out, but he finds solace in a new acquaintance. Falk and the Post & Telegraph brigade find a renewed energy in their fight against Radio Mercur in the form of new graduate Gitte, who has been employed as a clerk. Stenbæk threatens to start a competing radio station and Schiøler finds it hard to stay away from the drink after a catastrophic meeting with Aktuelt.
Radio Mercur and DCR are fighting for listeners and advertisers, and it becomes clear that they can’t both survive. The pressure from DCR also extends to family life for Flemming and Anne-Marie, who are forced to work more and more. Meanwhile, Jan buys an apartment to persuade his secret boyfriend, Peter, to move in with him, and Gitte shows her loyalty to Radio Mercur.
Radio Mercur prepares for its final broadcast. While the others are preparing for their future, Jan refuses to accept the station closure, and his manic struggle for survival starts to affect his relationship with Peter. Flemming tries to make sense of the past and the future and must come to terms with the fact that his future is now completely open. Gitte’s return to his life forces him to make a difficult choice. Jan decides to invite his mother to dinner so that she can meet boyfriend Peter.
Jan’s fate lays like a heavy cloud over the remnants of Radio Mercur, but Flemming strikes a final blow for the radio station. They quickly find support in the radio station’s many friends, and soon illegal pop music is playing again – to Falk’s huge frustration. Anne-Marie has trouble finding a way back and seeks advice from an old friend, as she finds no support from Flemming. Lily has a confrontation with Peter at Jan’s apartment, and Flemming makes his final decision for the future.