The pickled Martian's tentacles are fraying at the ends and Professor Coffin's Most Meritorious Unnatural Attraction (the remains of the original alien autopsy, performed by Sir Frederick Treves at the London Hospital) is no longer drawing the crowds. It's 1895; nearly a decade since Mars invaded Earth, chronicled by H.G. Wells in THE WAR OF THE WORLDS. Wrecked Martian spaceships, back-engineered by Charles Babbage and Nikola Tesla, have carried the Queen's Own Electric Fusiliers to the red planet, and Mars is now part of the ever-expanding British Empire.
The less-than-scrupulous sideshow proprietor likes Off-worlders' cash, so he needs a sensational new attraction. Word has reached him of the Japanese Devil Fish Girl; nothing quite like her has ever existed before.
But Professor Coffin's quest to possess the ultimate showman's exhibit is about to cause considerable friction amongst the folk of other planets. Sufficient, in fact, to spark off Worlds War Two.