During the summer vacations, the three friends are about to take a trip together to Romania, where they are allowed to complete an internship on the film set of "Dracula Rises", arranged for them by Peter's father, who is responsible for the special effects during the filming. No sooner do they arrive in Transylvania than mysterious events begin to pile up at Countess Codrina's old castle, which serves as the original setting for the film. The three detectives want to find out what all this may have to do with a boy who has been missing for over 50 years, a mysterious brotherhood and an enigmatic undead. Soon, not only the filming and Peter's relationship with his father are at stake, but also the friendship of the three investigators.
Unfortunately the movie The Three Investigators and The Legacy of the Dragon is not yet available on HBO Max.
| Production | Martin Bachmann | Producer |
| Art | Marius Bardasan | Leadman |
| Crew | Ionut Dobrescu | Assistant Picture Car Coordinator |
| Directing | Stefania Maftei | Second Assistant Director |
| Production | Sofie Scherz | Line Producer |
| Production | Lisa Tretrop | Line Producer |
| Art | Celina Hollaender | Art Direction |
| Sound | David Reichelt | Music |
| Costume & Make-Up | Margo Stefan | Key Hair Stylist |
| Art | Iulian Bostănaru | Art Direction |
| Production | Mara Fiedler | Producer |
| Production | Max Wiedemann | Producer |
| Production | Daniela Tolkien | Casting |
| Production | Ayhan Üsük | Production Manager |
| Costume & Make-Up | Frauke Pira | Makeup Department Head |
| Production | Valentino Rudolf | Line Producer |
| Directing | Cristina Iliescu | First Assistant Director |
| Costume & Make-Up | Svenja Gassen | Costume Design |
| Production | Justyna Müsch | Producer |
| Crew | Catalin Varga | Picture Car Coordinator |
| Art | Andreea Popa | Set Decoration |
| Art | Vraciu Eduard Daniel | Art Direction |
| Production | Oliver Lüer | Production Manager |
| Art | Bianca Micu | Assistant Set Decoration |
| Production | Quirin Berg | Producer |
| Production | Johanna Bergel | Producer |
| Art | Josef Brandl | Production Design |
| Crew | Daniel Rohm | Post Production Supervisor |
| Production | Stefan Gärtner | Co-Producer |
| Production | Adrian Pavelescu | Unit Production Manager |
| Sound | Christoph Oertel | Foley Mixer |
| Sound | Matthias Schmidt | Dialogue Editor |
| Visual Effects | Tonio Freitag | 3D Artist |
| Camera | Bogdan Stanciu | "B" Camera Operator |
| Crew | Georg Wesch | Production Intern |
| Visual Effects | Florian Ast | Visual Effects Supervisor |
| Visual Effects | Stefan Müller | Digital Compositor |
| Visual Effects | David Schuster | Digital Compositor |
| Production | Aleca Ivan | Production Coordinator |
| Visual Effects | Vanessa Foermer | Animation |
| Camera | Andrei Zikieli | First Assistant Camera |
| Sound | Martin Langenbach | Foley Artist |
| Camera | Bogdan Stanciu | Steadicam Operator |
| Editing | Sam Pluemacher | Assistant Editor |
| Lighting | Cristian Iacob | Electrician |
| Costume & Make-Up | Simona Alecu | Set Costumer |
| Camera | Antonio Diaz Gallardo | Key Grip |
| Directing | Nina Kötter | Script Supervisor |
| Costume & Make-Up | Ciresica Cuciuc | Costume Supervisor |
| Production | Catalin Dobre | Production Assistant |
| Art | Bogdan Voiculescu | Graphic Designer |
| Sound | Jürgen Göpfert | Sound Mixer |
| Visual Effects | Christopher Hummel | Digital Compositor |
| Lighting | Mihai Granaru | Electrician |
| Camera | Zsolt Tofán | Second Assistant Camera |
| Visual Effects | Jakob Kardoeus | Digital Compositor |
| Sound | Dana Hopfe | ADR Supervisor |
| Visual Effects | Sebastian Nozon | Visual Effects Supervisor |
| Camera | Ionita Valeriu-Mihai | Key Grip |
| Camera | Marian Bugeac | Grip |
| Lighting | Lucian Diaconu | Gaffer |
| Lighting | Vasile Dodu | Best Boy Electric |
| Crew | Jonathan Roth | Post-Production Manager |
| Production | Sabina Rudolf | Producer's Assistant |
| Visual Effects | Knuth Möde | Matte Painter |
| Editing | Markus Baburske | Colorist |
| Visual Effects | Claus Lunt | Digital Compositor |
| Lighting | Adrian Dobre | Electrician |
| Costume & Make-Up | Bastian Stein | Assistant Costume Designer |
| Writing | André Marx | Novel |
| Camera | Holger Jungnickel | Director of Photography |
| Writing | Anıl Kizilbuga | Writer |
| Writing | Tim Dünschede | Writer |
| Directing | Tim Dünschede | Director |
