Tatoe Hai Ni Natte Mo

from mangahelpers for his beloved younger sister's treatment, shinomiya ryouma is working frantically to raise a billion yen while going to high school. one day, a mysterious woman asks him, “can you put your life on the line for what you desire?” and after receiving a ticket from her, an accident befalls him! when he wakes up, he finds he's turned into a girl and what's more, he's participating in a “game” where a win means he can reverse his fate but a loss means he'll die instantly! (euthrosyne)