Sherlock Holmes y el Doctor Watson tendrán que desentrañar misterios con el Doctor Moriarty en la oscuridad de lo que les va sucediendo...
 | Ralph Fiennes | Moriarty |
 | Hugh Laurie | Mycroft |
| Rebecca Hall | Dr. Grace Hart |
 | Will Ferrell | Holmes |
| Kelly MacDonald | Mrs. Hudson |
| Lauren Lapkus | Millie |
| Noah Jupe | Doxy |
 | John C. Reilly | Watson |
| Pam Ferris | Victoria |
| Rob Brydon | Lestrade |
| Bronson Webb | Jonathan Nightingale |
| Bella Ramsey | Flotsam |
| Michael Culkin | Over |
| Kieran O'Brien | PC Smalls |
