The Film is set in Switzerland, at the beginning we see a drugged looking boy (Thomas) fall out of a boat on a lake. In the next scene, Martin Kurat (Jürgen), a homosexual actor, is on his way to the hospital, where the boy is being treated. He is in a coma but gave Martin's name several times, so they contacted him. The physician asks Martin, whether he can imagine, why the boy tried to commit suicide, what he knows about the story behind it.
The film goes back into the past then and Martin remembers, how it all began. Martin had been sentenced to prison because of an affair with an under aged boy. In prison he is actually treated quite well. The prisoners have had for a while the plan to put a play on stage, that one of them has written and now, that they have a professional among them, they can go ahead. They can't fill all the roles with prisoners, so the son (Thomas) of one of the wardens also takes part. Thomas has been aware of being homosexual for a while and when one of the older prisoners warns him that Martin Kurat is a danger for beautiful boys, he gets interested. He starts a conversation with Martin, secretly gives him a bottle of some kind of alcohol as a present and writes him a love letter but Martin does nothing to encourage the boy.
The play is a great success. Afterwards, when the prisoners are locked in again, Martin finds, that Thomas has managed to smuggle himself into his cell. He is appalled at first about this stupid idea, which is quite a risk for both of them. But they end up sharing Martin's evening meal, talking for hours about life and then end up making love. Martin asks Thomas whether it was his first time and it is, almost. He once tried something with a boy on a school trip, they were caught by the priest and had to wash the dishes for the rest of the trip.
In the morning they have to take great care to get Thomas out again undiscovered. Before Thomas leaves, he tells Martin that he loves him and wants to live with him, once he is out of prison. Martin tries to talk him out of it and to be careful, because he knows, how hard it is to be a homosexual. But Thomas keeps writing very nice love letters. Unluckily, one of these letters gets intercepted and Martin has to serve his full prison sentence, which was to be shortened because of his good behaviour.
Finally Martin is released and goes back to his old life. One night Thomas turns up unexpectedly and stays over night and they both agree, that they want to stay together. But Martin wants everything to be open and above board, Thomas is still a minor, and insists on seeing the father of the boy. The father is completely disgusted by the idea of his son being homosexual and doesn't believe it, he thinks he has been seduced by Martin. After a terrible row, the father forbids Thomas ever to come back home. His father had gotten Thomas a job as an apprentice in a shop, although Thomas would have preferred to continue school and study. After the quarrel, the parents see to it, that the shop owner knows about his homosexuality and Thomas has to leave. Martin and Thomas find a flat together and Martin lets Thomas go back to school.
But this idyll doesn't last very long: the police come to get Thomas. He is still a minor and "kept" by Martin, which is against the law, that protects children. Because he is in danger of being "corrupted", Thomas is sent to a special institution for borderline-criminal boys. When he arrives, everybody knows already, that he is homosexual and he is in for a very bad time, both by the other inmates and the wardens. He writes desperate letters to Martin, none of which gets sent, of course; instead he is treated even worse. At one stage, he manages to run away, just long enough to make a telephone call to Martin. It turns out, that Martin too has written letters, which never arrived. But he has a plan, that may work. When he is about to tell, Thomas is discovered and dragged back again. As a special "treat", a sadistic warden tells some other inmates, to make a man out of Thomas. Some of the boys have discovered a mentally retarded girl, which will let them have sex with her and the next time, they sneak off to see her, they drag Thomas along.
Meanwhile Martin gets himself a faked passport and pretends to be a psychology student, who wants to gather material for his thesis in Thomas' institution. The plan works, but after a few days, Martin gets sacked, because he made fun of the sadistic warden in front to the boys. Still, Martin and Thomas have managed to make a plan for a flight.
Thomas runs away in the middle of the night and they both go straight to the train station and take a train to germany. Martin knows a politician in Bonn, who may help Thomas to get the right papers to be able to stay in germany. If he goes back to switzerland, the police will bring him right back to the institution. The politician, Krauthagen, is also a homosexual, with an extensive pronography collection.
Thomas stays with Krauthagen, who promises to get the papers, while Martin goes back to Muenchen, where he works in the theater. It turns out after a few days, that Krauthagen has promised the papers and to treat Thomas as his son, even to send him to school, in exchange for Thomas becoming his boyfriend. Thomas is so terrified of going back to the institution, that he agrees, in spite of still loving Martin and feeling like a swine for agreeing.
Martin tries to accept this but after several weeks gets a telephone call from Thomas, who has been thrown out by Krauthagen. The promises where all lies and when then Thomas refused to sleep with Krauthagen, he found himself on the streets, forced to sell himself. Martin offers to go at once and meet him, but Thomas has just called to tell him, that he is going back to the institution voluntarily. He feels so disillusioned and disgusted with himself, that he doesn't want to go back to Martin.
Some time later, one of the old inmates from the reform school, who is officially released, visits Martin to tell him about Thomas. Apparentely, Thomas has been completely broken, he does everything, that is expected of him and shows no sign of his own will anymore. He is about to be released too, but as he has no intention of contacting Martin, this fellow inmate thought it would be a good idea to tell him.
Martin meets Thomas and takes him home. Thomas drinks a lot of alcohol and tries to keep Martin at a distance, by telling him, that the whole affair had never been love from his side, that it was all a lie right from the start. Martin doesn't believe him and tries to make him forgive himself, because what could he have done under all these awful circumstances? They end in each other's arms once more, but there is no happy end. Early next morning, Thomas goes out onto the lake in a rowing boat with lots of sleeping pills in his pocket.
In the next scene, Martin gets a call from the hospital, where the film started. The physician treating Thomas, who has listened to the story, calms Martin down and says, it will get alright.
But in the last scene of the film, Martin watches the news on TV, where they broadcast a search for Thomas, who has gone missing from the hospital and is supposed to wander about somewhere in a depression. People seeing him, are requested to speak to him gently and contact the police.