As the bombing of the Shinsengumi headquarters nears, Hijikata and Okita are still unable to find any means for escape. Only one key exists to unlock the shackles chaining each other. But if the key is used, it will set off a bomb to kill the other. The rule of the devil begins to stir distrust between the two. Though he commends them for not betraying one another, Jigzaw pressures them to make the final decision by displaying a certain item.
Then what are all the only children in the country supposed to do?
¿Qué podían hacer entonces 
los hijos únicos del país?
E o que filhos únicos fazem daí?