There is good reason for Sir Douglas Wonderly to summon the family and a lawyer to his stately home. He wants to announce a change in his will. At the same time, a dangerous mental patient escapes from a nearby psychiatric ward. Higgins and Lane are put on his trail. But the arrest of the psychopath proves to be extremely difficult. Shortly thereafter, a mysterious hooded man is on the loose in the castle. He frightens Sir Wonderly so much that the old man suffers a shock and falls into a coma. But that's not all: the will suddenly disappears and two sons are murdered. Sir John personally intervenes to solve the case with Higgins and Lane.
Unfortunately the movie Das Schloss des Grauens is not yet available on HBO Max.
| Directing | Wolfgang F. Henschel | Director |
| Writing | Edgar Wallace | Writer |
| Writing | Bernd Eilert | Writer |
| Production | Horst Wendlandt | Producer |
| Camera | David Slama | Director of Photography |
| Costume & Make-Up | Uli Simon | Assistant Costume Designer |
| Production | Angela Marquis | Casting |
| Crew | Hans Seck | Special Effects Technician |
| Editing | Sabine Brose | Editor |
| Sound | Stephen Keusch | Music |
| Sound | Andreas Walther | Sound |
