You broke the lamp. It was an accident — you were messing about where you shouldn't have been. When your mum came in and saw it, she immediately assumed it was your little brother, who's always knocking things over. He started to protest, confused, and you... said nothing. You let the silence point at him. He got told off. He kept saying "but I didn't!" and nobody believed him. You watched it happen and stayed quiet, because staying quiet was easy and owning up was scary. Now he's sulking, wrongly blamed, and you're holding a secret that's getting heavier by the minute.