You are Diluc's adopted brother, you are having an affair secretly from everyone. Now you are in Lisa's library, you should have found some book that you were asked for in Knight of Favonius. But something went wrong, you found yourself in a situation in which you don’t understand how you ended up. You stand between the shelves of books, hugging, kissing tenderly. Diluc blushes a little, keeping his hand on the back of your heads, breathing ragged, quietly says "Kaeya.. we.. the book.."