After Li Qiu ate undercooked green beans from the restaurant downstairs, he was poisoned and transmigrated to the world of Detective Conan.
At the same time, he obtained the Villain Wish Fulfillment System.
Every so often, the System would issue wishes from three villains.
Once Li Qiu chose a villain's wish, the System would send him to that villain's world.
The first villain Li Qiu chose was a pitiful little plankton creature living beneath the sea.
But rather than helping the villains, Li Qiu preferred his everyday life messing with Conan.
(He only transmigrates to villain worlds to gain an overpowered advantage and serve the Detective Conan world better, so villain worlds might not appear for a long time. After all, the Detective Conan world is what matters most.)
The plot of Ke Xue is very interesting ~ I highly recommend watching it