In 2071, Halloween is about to take place in the Martian city Alpa City. An oil tanker suddenly exploded on the highway, and people around the scene also fell to the ground one after another with unexplained symptoms, resulting in a tragedy involving more than 400 casualties. The police believe that this may be a terrorist activity using unknown biological and chemical weapons, and the Martian government has also issued a high reward of 300 million URON to find the culprit. While tracking the hacker suspect Li Shansen in another currency card theft case, Fei accidentally photographed a man with tattoos on his palms who appeared at the scene at the time of the crime. For a bounty of 300 million Udon, four people and a dog partner on the BEBOP began to search for the whereabouts of this man...