|The Eternity Injection|
|Directed by||Christine Moore|
|Written by||Robert Doherty, Craig Sweeny|
|Air date||8 January, 2015|
|Previous||"End of Watch"|
When a nurse Watson used to work with asks for her help finding their missing acquaintance, the woman's trail leads Watson and Holmes to another person who has disappeared. Also, Sherlock struggles with his sobriety when he finds the recovery process monotonous.