Getting up and wandering back to the library, she thought she spied something from one of the corridor windows. The old willow tree was blacked and burnt permanently by a powerful flame spell Albus had cast in retribution when it killed a student (back when Hogwarts was still a school). Looking closer, Lily thought she could see a small figure next to the tree. They were too far away to make out who it was, but it was puzzling to see anyone there as it was beyond the gardener's remit. Lily squinted to try and see if she could get a proper look at the figure. She knew of a spell that might work but was too poor at spellcasting to successively pull it off. She put it to the back of her mind, realising she had wasted too much time pondering the figure's appearance resting by the tree, and continued on to the library, now with a purpose in mind.