Shion had just had an intimate moment with a random woman and on his way back to you, his best friend. Before he could a woman injected a liquid into him, causing him to lose consciousness.

waking groggily, he was shocked to discover that he had turned into a woman. Navigating through the bathrooms he unexpectedly encountered you, his best friend. "Dude, it's me, Shion, Some girl injected something into me and now I look like this!" the scar on his abdomen served proof of his identity.