De veertienjarige Marco, een Roma-jongen, wordt aan de Deense grens aangehouden met het paspoort van een vermiste ambtenaar op zak. Inspecteur Carl Mørck en het team van afdeling Q onderzoeken het verband. De oorspronkelijke eigenaar van het paspoort blijkt kort voor hij verdween verdacht te zijn geweest van pedofilie en de zaak was opvallend vlug gesloten. Intussen weigert de stille, getraumatiseerde Marco met de agenten te praten. Hij slaat op de vlucht voor degenen die vinden dat hij te veel weet.
Nee, helaas is Het Marco-effect nog niet beschikbaar op Netflix in Nederland.
| Sound | Sune Martin | Music |
| Production | Sandra Foss | Line Producer |
| Lighting | Andreas Kragh-Jacobsen | Gaffer |
| Art | Gitte Malling | Production Design |
| Sound | Nino Jacobsen | Sound Editor |
| Production | Lina Wichmann | Post Producer |
| Production | Peter Nadermann | Co-Producer |
| Writing | Martin Zandvliet | Co-Writer |
| Costume & Make-Up | Susie Bjørnvad | Costume Designer |
| Crew | Hummer Højmark | Special Effects Coordinator |
| Production | Arwa Salmanova | Casting |
| Production | Wolfgang Feindt | Co-Producer |
| Costume & Make-Up | Tina Norup Helmark | Makeup Designer |
| Sound | Benjamin Hörbe | Sound Editor |
| Sound | Julien Naudin | Foley Artist |
| Production | Doris Schrenner | Co-Producer |
| Editing | Per Sandholt | Editor |
| Sound | Lars Ginzel | Sound Designer |
| Editing | Mette Lybæk | Editor |
| Production | Henrik Zein | Executive Producer |
| Editing | Per K. Kirkegaard | Editor |
| Sound | Frank Kruse | Sound Editor |
| Sound | Markus Stemler | Sound Editor |
| Writing | Thomas Porsager | Co-Writer |
| Camera | Aske Foss | Director of Photography |
| Crew | Jacob Sebastian Malm Carlsen | Stunt Coordinator |
| Production | Tanja Grunwald | Casting |
| Visual Effects | Martin Madsen | VFX Supervisor |
| Directing | Martin Zandvliet | Director |
| Writing | Anders Frithiof August | Writer |
| Writing | Jussi Adler-Olsen | Novel |
| Production | Mikael Chr. Rieks | Producer |
| Writing | Jussi Adler-Olsen | Writer |
| Writing | Jussi Adler-Olsen | Author |
| Camera | Martin Maryška | Focus Puller |
| Lighting | Daniel Kvarda | Gaffer |
| Costume & Make-Up | Charlotte Moe | Costumer |
| Sound | Sune Martin | Original Music Composer |
| Sound | Martin Saabye Andersen | Sound |
| Production | Greta Varts | Production Executive |
| Directing | Christian Bonke | Assistant Director |
| Writing | Denisa Marešová | Script Editor |
| Writing | Ditte Sun | Script Editor |
| Directing | Jette Keedus | First Assistant Director |
| Directing | Jude Kimuli | Third Assistant Director |
| Production | Malou Wiesneck | Production Manager |
| Production | Søren Frimodt-Møller | Production Manager |
| Production | Mascha Ott | Production Coordinator |
| Production | Fie Gehrs Madsen | Production Coordinator |
| Production | Nawa Al-ani | Producer's Assistant |
| Writing | Anders Thomas Jensen | Script Consultant |
| Production | Kristina Kornum | Line Producer |
| Production | Christina Pind Rasmussen | Production Manager |
| Camera | Mikkel Find | "A" Camera Operator |
| Camera | Johannes Sprogøe Fletting | "B" Camera Operator |
| Camera | Asker Frølund Andersen | Assistant Camera |
| Camera | Mikael Kort Kristensen | Grip |
| Camera | Philip Cooke | Assistant Grip |
| Camera | Kristian Appel | Steadicam Operator |
| Camera | Franz Borde | Focus Puller |
| Camera | Franz Borde | Steadicam Operator |
| Camera | Martin Samsøe | Focus Puller |
| Camera | Martin Samsøe | Steadicam Operator |
| Camera | Rune Johansen | Drone Cinematographer |
| Camera | Alex Suhr | Drone Cinematographer |
| Camera | Klara Crvckova | Still Photographer |
| Sound | Lars Gerrild | Boom Operator |
| Costume & Make-Up | Emilia Imperatore Bjørnvad | Costume Assistant |
| Costume & Make-Up | Sascha Valbjørn | Costume Assistant |
| Costume & Make-Up | Charlotte Hertz | Makeup Artist |
| Costume & Make-Up | Josefine Ranch | Makeup Artist |
| Production | Pavel Muller | Producer |
| Production | Veronika Skorepova | Line Producer |
| Production | Madara Kalnina | Production Manager |
| Visual Effects | Katharina Bormann | Visual Effects Coordinator |
| Sound | Martin Hedegaard | Original Music Composer |
