Bourbon's primary mission was to search for the escaped scientist Shiho Miyano, which the CIA spy Kir heard about and informed the FBI of. He also had a second secret mission fueled by his hunch that his archenemy Shuichi Akai should not have died so easily;[4] he received the boss's permission to verify Akai's death. He approached the FBI as an Akai lookalike by using Vermouth's disguise help hoping to see if Akai was truly dead.[15] He later apprenticed himself to Kogoro Mouri because Bourbon suspected the detective may be connected to Sherry.[16] (Kogoro was previously suspected of being linked to Sherry because the tracker, microphone, and gum combo Gin found on Kir's shoe after the Ding Dong Dash case was the same style as the one Gin discovered in his car that Sherry supposedly planted.)
Currently, Bourbon thinks Shiho has been killed,[17] and had come to believe Akai was dead as well until a suspicious man shrouded by smoke threw a grenade by him on the Mystery Express.[14] The sighting caused Bourbon to second guess himself and request that Vermouth show him the detailed files from before and after Akai's death again.[14] Bourbon has also decided to continue as Kogoro's apprentice because he noticed Conan is the real brains behind "Sleeping Kogoro" and is curious