Told through a series of Gossip Girl blasts, GG tell us the story of how Chuck Bass and Sherlock Holmes helped solve each others problems. Set during S5 of Gossip Girl and after The Fall in Sherlock.

Blair and Dan run into Sherlock on the streets of NY. What exactly does sherlock deduce? Dair

Blair witnesses a murder and Sherlock is recruited to investigate. Watson and he travel to New York to solve the mystery because the last victim of this serial killer, the one Blair witnessed, was the daughter of an English dignitary.