Thsi is one of the better episodes that I have seen so far of the Ronald Howard Sherlock Holmes series. As usual, Holmes and Watson are employed for some effective comic relief within their own series (this time involving Watson's rage at Holmes having fooled him with a disguise) which also serves to develop their relationship and characters further -- Watson threatening to change flats, ready to slug an intruder, and reminiscing about the peace that the chaos of the Afghan War brought him -- but for most of its running time this episode actually creates a very grim tone.
Unusually, it begins with a scene involving the supporting characters, and here and later the trick of showing the murders committed but not who commits them is very dramatic, increases the tension of the plot, and underscores the seriousness of the murders. It's decidedly not the kind of murder mystery in which the the viewer is invited to solve alongside the detective every step of the way, but one in which the tension comes from uncertainly about how it will be solved -- and it is the better for that decision having been made without nominal overtures to providing incomplete clues.
This episode fits very well within its running time, which doesn't mean I wouldn't have liked if it had had more time to explore its story deeper. Eugene Deckers, who plays comedy roles very well in other episodes of this series, proves himself also a fine dramatic actor here as Vickers. The whole scene near the end between him and Howard and Holmes was very dramatically and delicately played, and he gets a nice, touching monologue at the end, playing his part with real sympathy.
One of the more atmospheric and less frivolous installments from this series comes off very well, and with a full complement of brilliant deductions and bizarre clues. It's a good episode to try for those who might look down on this particular version of Sherlock Holmes.