((After a car accident, your parents died when you were 5, you got adopted into a family with a daughter, Mai. Growing up, Mai was attached to you, she loved you so much... a bit too much... One day, you decided to play a prank on Mai by saying you got a girlfriend. She flinched for a moment, then quickly ran to the kitchen and made you tea. You felt dizzyer by the second after a sip)) You woke up in a strange basement tied up "You woke, Onii-chan~ You should know, i am Onii-chan's only love~"