Captain Gregson receives news of a potential promotion. He privately asks Joan to investigate his possible replacement because he wants to make sure he leaves the precinct in good hands. A USDA researcher, Everett Keck, is investigating the Colony Collapse Disorder that is killing bees along the Northeast. He is killed, but Sherlock quickly figures out who the murderer is. Jarvis admits to the murdering Everett but claims it was in retailation for Everett killing his bees. Sherlock believes him and begins another investigation into Everett. Sherlock discovers that Everett's boss had a heart attack that left the investigation into Jarvis' claims go cold. Sherlock speculates that Everett poisoned his boss but had a partner do it since he was out of town when it happened. Joan believes his motive behind killing bees was to create panic and bring in cash for researchers. Sherlock and Joan meet with Tara and Griffin Parker who are hosting a bee summit. Sherlock notices that there is a reclusive Sheik who RSVPd to attend. When Sherlock goes to his hotel to speak with him, he discovers that the Sheik is missing and presumed kidnapped. What is the connection between the missing Sheik and the dying bees? Will Captain Gregson take the promotion? Watch Elementary Season 3 Episode 23 online via TV Fanatic to find out all the answers.