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 Disney Plus.
| Production | Lisa Tretrop | Line Producer |
| Production | Daniela Tolkien | Casting |
| Costume & Make-Up | Frauke Pira | Makeup Department Head |
| Production | Adrian Pavelescu | Unit Production Manager |
| Visual Effects | Sebastian Nozon | Visual Effects Supervisor |
| Production | Max Wiedemann | Producer |
| Production | Ayhan Üsük | Production Manager |
| Directing | Stefania Maftei | Second Assistant Director |
| Production | Valentino Rudolf | Line Producer |
| Crew | Ionut Dobrescu | Assistant Picture Car Coordinator |
| Art | Vraciu Eduard Daniel | Art Direction |
| Costume & Make-Up | Svenja Gassen | Costume Design |
| Visual Effects | Tonio Freitag | 3D Artist |
| Crew | Georg Wesch | Production Intern |
| Production | Stefan Gärtner | Co-Producer |
| Art | Iulian Bostănaru | Art Direction |
| Production | Justyna Müsch | Producer |
| Art | Marius Bardasan | Leadman |
| Art | Bianca Micu | Assistant Set Decoration |
| Production | Sofie Scherz | Line Producer |
| Production | Oliver Lüer | Production Manager |
| Production | Martin Bachmann | Producer |
| Sound | David Reichelt | Music |
| Production | Quirin Berg | Producer |
| Visual Effects | Claus Lunt | Digital Compositor |
| Visual Effects | Knuth Möde | Matte Painter |
| Costume & Make-Up | Bastian Stein | Assistant Costume Designer |
| Editing | Markus Baburske | Colorist |
| Crew | Daniel Rohm | Post Production Supervisor |
| Costume & Make-Up | Margo Stefan | Key Hair Stylist |
| Art | Josef Brandl | Production Design |
| Art | Andreea Popa | Set Decoration |
| Directing | Cristina Iliescu | First Assistant Director |
| Production | Mara Fiedler | Producer |
| Production | Johanna Bergel | Producer |
| Art | Celina Hollaender | Art Direction |
| Crew | Catalin Varga | Picture Car Coordinator |
| Camera | Bogdan Stanciu | Steadicam Operator |
| Costume & Make-Up | Ciresica Cuciuc | Costume Supervisor |
| Sound | Dana Hopfe | ADR Supervisor |
| Sound | Christoph Oertel | Foley Mixer |
| Camera | Marian Bugeac | Grip |
| Camera | Ionita Valeriu-Mihai | Key Grip |
| Camera | Andrei Zikieli | First Assistant Camera |
| Costume & Make-Up | Simona Alecu | Set Costumer |
| Production | Catalin Dobre | Production Assistant |
| Art | Bogdan Voiculescu | Graphic Designer |
| Lighting | Adrian Dobre | Electrician |
| Lighting | Vasile Dodu | Best Boy Electric |
| Crew | Jonathan Roth | Post-Production Manager |
| Production | Sabina Rudolf | Producer's Assistant |
| Visual Effects | Florian Ast | Visual Effects Supervisor |
| Visual Effects | Vanessa Foermer | Animation |
| Visual Effects | Stefan Müller | Digital Compositor |
| Visual Effects | David Schuster | Digital Compositor |
| Production | Aleca Ivan | Production Coordinator |
| Sound | Martin Langenbach | Foley Artist |
| Visual Effects | Jakob Kardoeus | Digital Compositor |
| Editing | Sam Pluemacher | Assistant Editor |
| Sound | Jürgen Göpfert | Sound Mixer |
| Sound | Matthias Schmidt | Dialogue Editor |
| Visual Effects | Christopher Hummel | Digital Compositor |
| Lighting | Mihai Granaru | Electrician |
| Directing | Nina Kötter | Script Supervisor |
| Camera | Antonio Diaz Gallardo | Key Grip |
| Lighting | Lucian Diaconu | Gaffer |
| Lighting | Cristian Iacob | Electrician |
| Camera | Bogdan Stanciu | "B" Camera Operator |
| Camera | Zsolt Tofán | Second Assistant Camera |
| Writing | André Marx | Novel |
| Directing | Tim Dünschede | Director |
| Writing | Anıl Kizilbuga | Writer |
| Camera | Holger Jungnickel | Director of Photography |
| Writing | Tim Dünschede | Writer |
