Co-creator Steven Moffat's new episode goes by the name His Last Vow. That title is a reference to His Last Bow, the final Holmes story in narrative continuity, if not in writing order. It is likely, however, that the vow of the title also refers to the probability that this series will see the story arc in which Watson gets married and moves out of Baker Street. Moffat has referred to a desire to confront the notion that Holmes and Watson won't always be living together and this would seem to be the next interesting way that their relationship could develop while staying true to Doyle's writing. Even if the new series does not use His Last Bow as more of a source material than its title, it would be interesting to see it adapted in the future. More of a spy story than a murder mystery, His Last Bow finds the aging Victorian detective on the eve of the First World War and posing as an American informant passing military secrets to a German spy. Coming long before the age where spy thrillers were at their most popular and successful, His Last Bow has been criticised as being a lesser quality of work than some of Doyle's murder stories by pointing to the fact that Britain would have gained more by allowing Holmes to continue passing false information to the German spy than by capturing him. However, the TV series has always been at its best when subverting some of the stories' details, while its increased use of Mycroft Holmes' role in intelligence work would bear out a story set entirely in the world of espionage. However, with Sherlock still remaining fresh and exciting and the protagonist still youthful, the key element of an older Holmes reaching retirement and only coming out of it as a patriotic duty may have to wait a few series. After retirement, Holmes takes up beekeeping. Some reference to this interest or the book, Practical Handbook of Bee Culture, that he swaps for the military secrets would be nice to see.
