Rainy Afternoons are Bad

One rainy afternoon, a man seeks Lupin's help on behalf of a young woman. The woman is actually Fujiko, who is after a diamond known as "The Star of Killamanjaro". The diamond was implanted into the chest of a mob boss. This boss had his memory wiped but died days before it was to be restored. Now, Lupin and the gang are after the ambulance carrying the corpse and the diamond in it. Zenigata is in charge of the ambulance and its escort, and he attempts to prevent Lupin from stealing the diamond.