Keigo Westwood, nicknamed "Bullet", is a Wyoming police officer involved in the takedown of the Mexican drug cartel La Llorona. True to his name, he charges straight in and rushes through the cartel's defenses, leading to the arrest of all of its leaders. However, at that same time Yellowstone's volcano, which is said to be powerful enough to wipe out all of humanity, explodes. The earth splits, Keigo and the arrestees are swallowed up in it, and when he comes to Keigo is in the 19th century--the era of the Wild West. It is in this world, where all manner of men run free of the law, that Keigo teams up with a vengeful Abraham Lincoln in hunting down the members of La Llorona once again.