The cabin

And then on the day of the attack, Ryder clearly saw Lily sprinkle the dried petals of the flowers on Ava's meal. She then had argued with Ava, provoking her to the point where Ava hadn't been able to do anything but attack her. 

"I am such a fool." Ryder whispered to himself. 

"That's not true Ryder. Her plan was foolproof, you had no way of knowing that she was doing such a despicable thing." Evena answered. 

"Take me to the study." Ryder said, Evena snapped his fingers and they were in the study again. Ryder saw Ava standing alone and then Lily came in. The both girls exchanged words, Lily had mocked and taunted Ava and then Ava had attacked her. 

"Ryder, we have to go. Time is running out." Evena told him. 

"Let's go. I have nothing more to see anyway." Ryder replied. 

.......