Watch Unit One Season 3 in Australia

A psychology student meets up with one of her regular chat friends. After she disappears it takes six months before Unit One is on the case.

Christian and Andreas Dahl are shot when they confront two famous criminals in burying stolen money in Kalundborg. Tina Lauritsen, the wife of Christian, is later found with her throat slit. The criminals are quickly identified, as a burned out white Mercedes is found containing rabbit dung (as Eik Nielsen, the male criminal, favours white Mercedes and Anja Jespersen, the female criminal, always carry around a rabbit). Unit One puts the area where the money was buried under surveillance. When the couple shows up, the Special Police Corps surround them, but they manage to escape into the church where a small group of people were arranging baptising schedules. Eik lets the grown ups escape and the priest, the wife of a local police officer, manages to text message Unit One and ask them to open the Northern Door to let Anja escape with the infant. The Special Police Corps manages to successfully rescue the priest and take Eik into custody.

Unit One is called to Aabenrå when parts of a woman body is found in Knapsø. As Unit One checks the German Missing List, a witness tells of a silver Audi from where a man tossed a trashbag into the harbour, and of a burning container filled with personal files on a Doris Fröse. The owner of the silver Audi, Manfred Schlosser, lacks any information. A summerhouse owner contacts them and tells that the sheets and beddings have been replaced and the floor scrubbed very thoroughly. Blood samples confirms the victim to be Doris Fröse, but the name of the man who borrowed the summerhouse is fake. A friend of Doris Fröse confirms that the man whom Doris Fröse was visiting in Denmark was Manfred Schlosser. In the mean time, Pernille, the wife of Manfred Schlosser, finds knives and photoalbums of many murdered women in the attic. Manfred finds out and drowns her in their bathtub. Manfred is taken into custody, but denies everything.

A hotel is set on fire in Nyborg, killing 32 people. A local pyromaniac, Henning Jørgensen, is taken into questioning, but fails to answer where the fire started. In a side story, a little boy witnesses how a bespectacled man places the corpse of a young woman on a bench in a parking lot. In a picture from the local newspaper, a face is very faintly viewed in the background, and the police trace the person in the picture to be Otto Lykke Larsen, a mentally retarded man. Larsen is taken into questioning. In the videos found in Larsen's apartment, fires are videotaped and Unit One suspects that Larsen was the pyromaniac responsible. In other videos, Larsen has sexual intercourse with a woman, Britt Hjort Jespersen. In questioning, Larsen admits that he was the one who set fire on the hotel, along with all the other fires recorded in his videotapes. In the mean time, the corpse of the young woman is identified as Jespersen. Larsen admits he killed Jespersen.

Just released from prison the entrepreneur called farmand (daddy-o) is found murdered in a Danish train to Århus, which puts the unit smack in the middle of hypnosis and crime and they meet one of the smartest criminals in the series so far. Kaare commits a robbery just after being released from State Prison in Horsens. He shoots three people and is arrested by Fischer. Unit One suspects that Ivan has masterminded the coup.

The tragic case of Kaare and Ivan continues, who will break first the police or Ivan?

Bertel Kjeldsen calls Dahl late at night to ask her to come to Fredensborg where he allegedly killed his own wife. In the meantime, the case of Britt Hjort Jespersen is brought up again as a poor autopsy of the body wasn't satisfactory. DNA samples from a new autopsy show DNA from another man. Dahl tries hard to find Keldsen, who is standing at the edge of a tall building when Dahl finds him. He tells how he killed his wife and how his son, Knud Kjeldsen, killed Jespersen. Dahl arrests Knud. Knud lies under questioning, but the DNA samples show that Knud's biological brother, Robin Hansen, who is mentally retarded, was the murderer. Knud tried to cover for his retarded brother to spare his family.

When local crime boss Bob is found murdered in his own S&M dungeon in a custom made monkey cage in Fredericia, the unit is involved in a case of revenge and jealousy.

An entire family is brutally murdered and the case leads the unit into a tragic story of incest and violence.

Jette Møller is found murdered in a fish boutique in Vordingborg. Finn Møller, her husband, is taken into custody, but nothing is gaining out of his answers. Her phone is tapped and when a suspicious phone call remind Fischer and La Cour about Strangers on a Train, Møller is put under surveillance. He escapes when he sails from Vordingborg to an island. The following day, the body of Putte Bech Lorentzen is found in a sauna. Unit One suspects Larsen and arrest him. Through evidence found in the garden of Bech Lorentzen, Unit One arrests Bertram Bech Lorentzen, the husband of Putte, for the murder of Jette.

A young girl is found murdered on Bornholm and the unit is quickly involved as it looks like the work of one of Denmark's infamous serial killers, known as The Indian; unfortunately, the story spins into a personal tragedy for Ingrid.

When Johnny finds a couple of Polish girls in the back of a truck near Slagelse the unit is getting involved in a case of human trafficking and quickly tie it to the Polish mafia.

La Cour gets one of his visions and finds a murdered student at one of the most prestigious boarding schools in Denmark, this involves the unit in a case where they finally get clues to find the serial killer known as The Indian (because he cuts the pubes off his victims); meanwhile, Ulf has bad news for the team.

The Indian has kidnapped Gaby, and La Cour and Fisher is on their tail, IP is trying to protect The Indian's ex-girlfriend who are also the murdered student's sister; this dramatic episode was supposed to be the end of the series, but as you can see below, two episodes were added later.