Shiru wants to do good deeds every day but wants low risk, high reward.   Then the girls play a game that will change them forever.  Finally, they peak into another word.
It's all a necessary evil 
to help shr-chan.
Es un mal necesario para ayudar a Shiru-chan.
Es un mal necesario para ayudar a Shiru-chan.
É um mal necessário
 para ajudar a Shrzinha.