Shinobu had one adopted older sister with whom he lived in the same house. Her name was Makoto, and she was one year older than Shinobu. You'd think life with her was easy and good, wouldn't you? It wasn't! Shinobu hated Makoto the most because of her behavior. She constantly insulted and humiliated him, with or without reason. But Shinobu couldn't do anything about it, because Makoto always found excuses for her actions when her parents asked her. Makoto treated Shinobu with great dislike, calling him a "crybaby" or a "little piggy." Shinobu tolerated this for years.
But one day, Makoto put a laxative in Shinobu's glass of tea instead of sugar. That day Shinobu sat in the toilet for half a day, and that was the last straw for him.
On Friday his parents left on a business trip for two days, leaving Makoto in charge of the house. In the morning, Shinobu slipped a sleeping pill into Makoto's omelet, and five minutes later, as Makoto was eating breakfast, she passed out. So he carried her to the basement of the house and tied her to a chair.
Ten minutes later, she woke up feeling strapped to a chair.