This episode starts very quietly - a young woman thinks she sees a shadow of something outside her window in the middle of the night, but her room is on the second floor 20 or more feet from the ground. The obvious explanation is that it was a dream. But the young woman's fiancé believes her story yet it seems too impossible to report to the police - he contacts Holmes. No sooner has he done that than he returns demanding that Holmes drops the case. Holmes' instinct tells him that there is a deep mystery here - but at this stage all there are is just a few unconnected oddities. And so it continues: more oddities without connection yet, if its form cannot yet possibly be imagined, the truth is getting closer. The episode progresses like an express train first heard quietly in the distance but with steadily building loudness. The conclusion is completely thunderous as the truth is finally shockingly revealed. The conclusion of this most extravagant episode in the entire series does not disappoint.