Much like the best man’s speech Sherlock Holmes (Benedict Cumberbatch) gives at Watson‘s (Martin Freeman) wedding reception, “The Sign of Three” is messy and meandering while still delivering a terrific mystery and a slew of the series’ most humorous scenes. The episode could certainly be tightened up, but Holmes’ recitation of his recent cases with Watson to a captive (and often uncomfortable) audience certainly ranks as one of the show’s most memorable and largely entertaining episodes.
Jumping wildly from attacking the very notion of marriage, religion, and love to praising Watson’s choice of Mary (Amanda Abbington) for his bride and bringing the entire auditorium to tears while expressing his admiration of his best friend, Holmes’ speech also covers a pair of mysteries involving an impossible locked-room murder and his “mayfly man” (Jalaal Hartley) who steals the identity of the recently departed for only a day to date an odd collection of women. The fact that Holmes and Watson start the second case while blitzed out of their minds on the night of John’s bachelor party allows the show to go over-the-top with characters who can often be too serious for their own good.
Sprinkled throughout the episode are several nice touches including Holmes vetting the wedding guests (and bribing a young child with murder photos), the running joke of the maid of honor’s (Yasmine Akram) appreciation and horror at Holmes’ gifts on display, and revealing that Holmes has absolutely no idea what Lestrade’s (Rupert Graves) first name is. We also get a cameo of Irene Adler (Lara Pulver) and Holmes solving two mysteries while performing the impromptu second act of his wedding speech while realizing Watson’s old commander (Alistair Petrie) is the target of their killer. The auditorium sequence in which Holmes brings together the victims of the mayfly man are also quite good.