This is the nightlock that started everything. Katniss pulled these berries out of her pocket to have Peeta and her kill themselves at the end of the 74th Hunger Games. This was seen as an act of defiance against the Capitol. The people of Panem started to rebel against the capitol. At first it was little things but it started to get bigger and bigger. Katniss told President Snow it was because of her undying love towards Peeta. President Snow told her if she cannot convince him that this is true then he will kill her family. So throughout this entire book up until the end she is trying to convince President Snow that she truly loves Peeta.